Help with floor heat

[cantbreak80]

slash,
How many bays? What's the outside air temp?
Re: infrared gun. Thye work best when aimed at non-reflective surfaces. So, a patch of the flat black spray paint or a wrap of non-shiny black tape on the copper piping will provide some reasonable data. Measure the outlet of the boiler...anywhere from the boiler's header to where the pipe feeds the manifold...maybe even at the tank's outlet. Then, measure the return pipe before the by-pass...the further from the by-pass the better. The difference between those measurements is the Delta T. With the system up to temperature, this should be in the neighborhood of 20 degrees. (it probably won't be)

Then, measure the temp of the inlet piping after the by-pass...it will likely be very close to the outlet temp. Report these readings and maybe we can make some suggestions. (I'm still stuck on the worn impeller thing). I'd also like to know if the "issue" is new or has it always short cycled.

Raypak recommends Ethylene Glycol...automotive antifreeze. That's what your photo looks like. With a 514,000 btu boiler...I'm thinking it's a 5 bay? Probably no more than two or three gallons will bring it up to the red line. Adding a gallon or two of straight antifreeze won't do any injury...it's going to mix just fine. Antifreeze is used because too often a power failure occurs during freezing weather and you don't want the system to freeze. While you've got the plug out of the tank, shine a light down there and observe the turbulence of the glycol...lots of volume is great. A "quiet" flow into the tank, not so much! Kind of hard to describe, but it should be "churning".

 

[cantbreak80]

Oh...you DID state it's a 5 bay, didn't you! (reading skills are failing me faster than I care to know!)

 

[2Biz]

CB80 spelled it out pretty well on what to do with the infra red gun. To take it a step further, I check my bays with it too. When setting the zone valves, I used the gun to check all the bays in different areas. Right now is a good time to do that since the system has ran long enough for all the zones to normalize. Then adjust the valves accordingly.

To me, like CB80 mentioned, you may have a bad impeller or the bypass valve is bypassing too much and not letting enough heated glycol to go out to the bay. Or possibly low antifreeze. If I remember right, since I had a zone in the trough, I had to fill it with the pump running so all the antifreeze wouldn't spew out when I took the cap off...Something to watch out for...But again, its hard to tell how your system is. Just something to watch out for. The coolant in the trough will seek the lowest point!

 

[slash007]

View attachment 730 View attachment 731 View attachment 732

To update, I went to the car wash today around 12 and the boiler was running. It was around 0 degrees and had gone down to -10. I went back around 3 to drop off some salt and it was off with the limit tripped. I left the limits the same, but adjusted the knob back down to 5.

I used the infrared gun to take some measurements as you suggested, but not sure if I measured the correct places. I added black tape and took some pictures to show what I measured. Another thing, since the boiler had turned off, it had only been on for around 45 minutes, so I don't know how accurate they #'s are. I measured right by the boiler outlet and it was 103. Near the inlet, it was 83. I then measured a spot as far away as I could from the inlet, before the bypass. There it was 50 degrees. If you look at the pictures, you will see the black tape in 3 spots, those are where I measured.

In regards to the glycol, I do have a loop in the trough so I worry about opening it to fill. I also worry about opening it while running. What is the safest way for me to fill it?

Also, is there a way to add pics that show up in the post as opposed you guys having to download to view? It used to work fine before.

 

[2Biz]

Is that a pressurized system? Is there a pressure gauge on the expansion tank or anywhere in the plumbing that you can see if there is any pressure on it? Any service valves?

You can upload your pictures to a free hosting service like Photobucket and link to the pictures. I like to resize to 600x800 and they are small enough (file size wise) but big enough to see detail.

 

[slash007]

Is that a pressurized system? Is there a pressure gauge on the expansion tank or anywhere in the plumbing that you can see if there is any pressure on it? Any service valves?

You can upload your pictures to a free hosting service like Photobucket and link to the pictures. I like to resize to 600x800 and they are small enough (file size wise) but big enough to see detail.

There is a pressure gauge on the tank, it's at around 18 psi. I also see a service valve on the side.

 

[2Biz]

See if this makes sense...I don't think you have a glycol issue. The pump draws from the bottom of the large tank. So as long as there is any glycol in the tank at all, then the system will work. The service valve you see is the Air Chuck to fill the system with air pressure after you've filled the system to the sight gage. If you want to fill it, try to bleed off the air pressure till the gage reads zero. I think you can use the air chuck as long as its above the fluid level. Then unscrew the large pipe plug on top and fill to the full line on the gauge. Reinstall the plug, Then fill with air pressure. My system is set to 12 psi....18 probably is ok....

Can you take a better picture of the pump and bypass valves from farther away. There's a lot of plumbing there. I can't figure out that vertical pipe with a green handle ball valve. From the looks of the highest yellow ball valve, your bypass is turned all most all the way off.

BTW...Don't worry about the trough zone. Remember "The finger over the straw" thing....The only way it could drain back is to suck air from up in the trough.

 

[slash007]

Here are a couple of pictures, let me know if they help. The bypass valve should be the one with the yellow handle that is directly above the 4" steel electric box mounted on the wall. View attachment 733

 

[cantbreak80]

OK...looks like it's supplying two distribution manifolds, one on each side of the building? The by-pass is indeed above the J-box and it appears to be nearly closed...so that's not the issue.

There's absolutely no need to have any pressure on the system, let alone 18 psi. It's a predominantly at grade system and should not require anything other than heat expansion pressure. The Schraider valve is below the liquid level in the tank so you'll not enjoy trying to relieve the pressure from there.

Since your purpose is to add glycol, it's ok if you open what looks to be a drain valve (with the green handle). Capture the glycol for reuse and when the pressure gauge is at zero, slowly open the plug on the tank. You're likely gonna need a long handle wrench or a cheater bar. Put a rag over the plug and loosen it until all the residual pressure is relieved. DO NOT LET GO OF THE PLUG just in case there's pressure still on the system. Then, fill 'er up to the red line. Turn the pump back on and observe the flow. Again, it should be significant.

slash...I gotta say...be careful. You might even want to just get through this freeze event and work on it when the sun comes back out. You're not going to lose any business until it warms up so here's my suggestion:

1. crank the manual HL to it's highest point
2. turn the Automatic HL down to 115-120 or so
3. Turn the gas valve down to 5 or so

This should keep the HL out of the territory while still allowing the boiler to produce some btu for the trough. The floors aren't going to stay ice free anyway...at least not until the ambient temperature gets above 10F.

Then, when you're not in a panic (not sayin you are in a panic...but I would be) you can shut the system down and work on it at a more leisurely pace.

 

[slash007]

Lol I am in a panic, this thing shutting off is killing me as it takes hours to clear the bays in this weather. Either way, I don't plan on messing with it until it warms up. Supposed to be above freezing this weekend, but that includes a rain/sleet storm so I plan on changing my boiler water storage tank that has developed a small leak. It started leaking about a week ago and I have been praying that it goes above freezing before the leak gets bigger so that I can shut off the water and change it.

In the meantime, I do have the manual limit set on max, the auto is still at 130, but I turned the valve down to 5. I hope it is still on tomorrow. Next week is supposed to be below freezing every day, so no relief there either.... Going to be a lot of fun

Thanks again for all of your help an patience as I try and figure this out. Once I add glycol and run the system, will it be safe to run it with the top of the tank off so that I can look inside?

 

[6t7gto]

I have the same RayPak.
Kept tripping the resettable limit.
Found out my heat exchanger was sooted up due to the gas valve vibrating to the highest setting.
Flame would roll out and trip the high limit.
I have mine set on 5 and zip tied it to stop the setting from moving.

 

[slash007]

I have the same RayPak.
Kept tripping the resettable limit.
Found out my heat exchanger was sooted up due to the gas valve vibrating to the highest setting.
Flame would roll out and trip the high limit.
I have mine set on 5 and zip tied it to stop the setting from moving.

Mine stays at the set # and doesn't move, so that can't be the issue. What do you have your limits set at? With it set at 5, at what temps can you stay ice free?

Thanks.

 

[slash007]

Just to update, I just spent about 4 hours at the wash replacing my boiler storage tank and even though it was 2am, figured why not mess with the floor heat I relieved the pressure on the glycol tank and my pressure gauge still read 18, so I realized that it didn't even work. I replaced the gauge then took the top off of the tank and added glycol. It just needed one gallon to reach the top of the red line. I then turned it on and looked inside to see how it was moving. I am not sure how much velocity there is supposed to be, but it was stirring around and on the side opposite the inlet, it seemed to bubbling up against the side about 1-2 inches.

I then put the top back on and added some air till it got to 5psi. I ran it again and after a few minutes it reached around 9 psi and seemed to stay there. Is that good? Also, does the velocity seem fine or do you still think I have a worn impeller?

Thanks.

 

[2Biz]

Slash,

You really didn't have to add air pressure like CB80 responded....Your system doesn't require it....Mine needs to be pressurized because I have an Expansion tank that is pressurized and my system has to be pressurized to match the amount of pressure on my expansion tank. Your tank is similar, but different. Its basically just a huge tank that allows for expansion and contraction. There is no bladder inside the tank like the Expansion tank I have...

So now that is out of the way...Do you know what cycles your boiler on and off? Do you have a slab stat or an aquastat on the return plumbing back from the loops?

You only need about 100° fluid going out to the bays to keep them ice free...And even that depends on the speed or volume the glycol is traveling through the zones. But I would think that is a good starting point. Assuming you have an Aquastat on the return piping, you need to cycle your boiler on at about 60° and then off at about 75°. To do this, you have to have an aquastat with differential. I have mine set at 15°....

So now to the fun part...Somehow you need to adjust the bypass valve so you have 100° glycol going out to the bays, while maintaining 130°-140° temp glycol through the boiler to keep it from condensating. And also keeping it away from the high limits that shut it off till its reset. Thats the balancing act that we're talking about. It takes a little while to achieve the sweet spot.

So now is where the heat gun comes in to play. You need to monitor the outgoing glycol from the boiler, or is there a temp sensor on the boiler that monitors glycol temp? This is what you use to set bypass volume to get the correct temp glycol in the boiler AND the correct Temp (100°) going out to the bays...Remember the 100° is taken after the bypass or at the zone manifolds. I also see (I believe) a sensor on the bottom of the holding tank....This I believe is one of your high limits...

If your unable to achieve this with adjusting the bypass, then maybe you have a worn impeller and your not able to pump enough fluid through the boiler to keep it off the high limits, like CB80 suggests...I hope this helps, its hard to diagnose all this through a few pictures without being there. Something else that comes to mind...Do you have a flow switch? Surely this isn't something else giving you issues? You have homework!

 

[cantbreak80]

Minimum flow rate through your boiler is 30 gpm. Did it look like at least 30 gpm?

The only reason to pressurize the system is to overcome the slight static pressure created by the trough loop...and that's probably only about 3-4 psi.

I just love the way the plumber stuffed everything into a nice tight arrangement...what the heck, he's never going to have to work on it, right? See if you can read the pump model number and motor HP.

You've never answered the question...has the boiler always short cycled or is this a new occurrence?

2Biz...yeah, that sensor should be the Manual High Limit. For some reason it's occasionally seeing excessive temperature.

 

[slash007]

Minimum flow rate through your boiler is 30 gpm. Did it look like at least 30 gpm?

The only reason to pressurize the system is to overcome the slight static pressure created by the trough loop...and that's probably only about 3-4 psi.

I just love the way the plumber stuffed everything into a nice tight arrangement...what the heck, he's never going to have to work on it, right? See if you can read the pump model number and motor HP.

You've never answered the question...has the boiler always short cycled or is this a new occurrence?

2Biz...yeah, that sensor should be the Manual High Limit. For some reason it's occasionally seeing excessive temperature.

Sorry, I forgot to answer that question. The boiler only started short cycling when I lowered the auto limit to 120. Once I went back up to 130 and lowered the gas valve down to 5, it isn't short cycling anymore. It stayed on for a couple of days now. My goal is to now be able to higher the temp just a little without it tripping the limit. I'll start by measuring the outgoing temp and seeing what that is.

About the flow rate, I honestly have no idea what 30gpm looks like, so I'm not sure

 

[2Biz]

Minimum flow rate through your boiler is 30 gpm. Did it look like at least 30 gpm?

2Biz...yeah, that sensor should be the Manual High Limit. For some reason it's occasionally seeing excessive temperature.

Which "May" explain your "Worn Impeller" diagnosis? With the bypass almost completely shut, and IF the pump was working right, that limit should never get hit....It might also explain the short cycling?

Slash,

I see you posted when I was typing...Glad to see it stay on for awhile..Did you ever see how the boiler is controlled? Slabstat or return glycol aquastat? Neither?

 

[mjwalsh]

Which "May" explain your "Worn Impeller" diagnosis? With the bypass almost completely shut, and IF the pump was working right, that limit should never get hit....It might also explain the short cycling?

2Biz, & Slash,

Just thinking outloud ... I have no regrets installing Gerand ball valves in strategic spots within our piping. These valves have 2 ports on them that allow measurement of actual flows. If I remember right ... the Gerand ball valves were not that much more expensive than regular full flow ball valves. I was watching on E-bay for the accompanying meter (verify flow ranges) that Gerand also sells so I got a pretty good deal on one of those too a few years back. For as often the meter could be needed though ... it kind of makes sense to have a local HVAC company do a quick check letting them be the ones to own the meter. If you are ready with a template made in spreadsheet program or whatever to write down as the technician goes from valve to valve ... you very likely would be just charged the minimum service call depending on the outfit.

mike walsh http://kingkoin.com/USA_Deficit_Reduction.html

 

[slash007]

I wanted to give an update on my floor heat issues. After trying most of the suggestions here with no luck, I reached out to a car wash operator that I know and he suggested that I call Raypak. I called and they were very helpful. The person I spoke to said that my symptoms sound like a dirty boiler or not enough fresh air coming in, and suggested I do a thorough cleaning. He also said to keep my manual limit around 160, the auto limit at 140 and the gas valve at 5.

On Tuesday I had it taken apart and cleaned. Boy were the coils on top filthy. Yesterday we had 17 inches of snow and last night it was -2, and it worked like a champ. Melted any snow and no ice on the bays! The only problem I had was that the temp was set too low, so by the time it kicked on it was already freezing rain turned to snow, so it wasn't warm enough yet to thaw it out and snow piled a bit. It all melted pretty quickly once it stopped snowing though. What temp you do you guys have it set to kick on?

After two years of scraping floors and pulling my hair out, I think that the issue is probably solved. I will keep an eye on it, but hopefully that's all it was. Thanks to all that responded and kept up with this thread.

 

[2Biz]

I have mine set to kick on at 32°. So, in theory, the slab will be warmer than outside air as the temperature drops. The heater should warm the slab from there. Does yours kick on by a T-stat based on outside air temp. I have mine set to come on using the secondary output on the weepmiser.