I.B. Washincars
Car Washer Emeritus
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Only if we want it to never be looked at againShouldn’t this thread be a “Sticky”!!!!????
Only if we want it to never be looked at againShouldn’t this thread be a “Sticky”!!!!????
6 self serve and an automatic and we replaced 2 million total btus. We have 1- 250,000 btu boiler that has heat exchangers plumbed in and it will do floor heat and other hot water with few problems. It is set up so that hot water is the priority so it just goes back to floor heat when hot water catches up. On those few days when we are backed up to the street busy the water is 100 degrees instead of 135. All that being said I think If I was to do it again I'd just have a conventional hot water tank for hot water and an instant hot water heater or condensing boiler for the floor heat with glycol run directly through it. If you don't care about standby losses you could use a conventional tank and recirculate it through the tank just like you're saying.I am planning on ripping out some boilers pretty soon too. I have done several tankless setups in the past. However, on these next ones, I am planning on using one tankless 400Kbtuh unit to feed hot pressurized water to a gravity tank. Then have one 400kbtuh tankless heater set up in recirculation mode to the gravity tank to keep it hot. The gravity tank will primarily fill with hot water, but I will have a lower float in the tank that will fill with cold water when the system demand is too much for the first heater. The t-stat for the recirc pump will be set about 5 degrees less than the fill tankless water heater will output, so the 2nd heater will only have to come on to 'keep hot' or to heat cold water coming into the tank during high demand. While this setup isn't new for me, the next part will be: I plan on ripping out the floor heat boilers (I really need the space) and installing a heat exchanger instead of the boiler. The heat exchanger will just be ran inline with the recirculation water heater. My only concern is that if the place looses power for a period of time during extreme cold, then starts up with below freezing glycol pumping through the exchanger - I may end up freezing the water side of the heat exchanger doing some serious damage. I may have to have some temp sensor that will protect this from happening and have to be manually ran til the glycol heats up some.... We will see how it goes. This should save some bucks. I will be taking out 2 million btuh worth of heaters to do the same job with 800kbtu. I hate seeing the 1.5 million btu boiler firing up for 4 seconds to heat up a 25 gallon tank 5 degrees when one customer is using a bay. What a stupid set up.
Neat idea! Something else to consider. I recently put in a 199K BTU 55 gallon HTP Phoenix all Stainless Steel Condensing/Modulating water heater. It has 1" supply fittings and additional 3/4" fittings for space heating capabilities. This would work great for your heat exchanger without tying it all in to your float/gravity tank. With this setup, One water heater will do the work of 2 demands with no restrictions. They make ones up to 119 gallon capacity. Maybe bigger? Just thinking about this from a different angle. I'm more than satisfied with my water heater so far. Extremely efficient to operate.I am planning on ripping out some boilers pretty soon too. I have done several tankless setups in the past. However, on these next ones, I am planning on using one tankless 400Kbtuh unit to feed hot pressurized water to a gravity tank. Then have one 400kbtuh tankless heater set up in recirculation mode to the gravity tank to keep it hot. The gravity tank will primarily fill with hot water, but I will have a lower float in the tank that will fill with cold water when the system demand is too much for the first heater. The t-stat for the recirc pump will be set about 5 degrees less than the fill tankless water heater will output, so the 2nd heater will only have to come on to 'keep hot' or to heat cold water coming into the tank during high demand. While this setup isn't new for me, the next part will be: I plan on ripping out the floor heat boilers (I really need the space) and installing a heat exchanger instead of the boiler. The heat exchanger will just be ran inline with the recirculation water heater. My only concern is that if the place looses power for a period of time during extreme cold, then starts up with below freezing glycol pumping through the exchanger - I may end up freezing the water side of the heat exchanger doing some serious damage. I may have to have some temp sensor that will protect this from happening and have to be manually ran til the glycol heats up some.... We will see how it goes. This should save some bucks. I will be taking out 2 million btuh worth of heaters to do the same job with 800kbtu. I hate seeing the 1.5 million btu boiler firing up for 4 seconds to heat up a 25 gallon tank 5 degrees when one customer is using a bay. What a stupid set up.
JGinther,MJ, My concern was that if the system somehow turned on when it was off for a long time (like if power was lost when below 0 out) and then came back on, the temperature of the incoming glycol would be cold enough to freeze the water side and damage the units... While I can work around this, it would be good peace of mind to know that freezing may not cause any damage. I wonder how in the world a water pipe could be freeze tolerant...? hmm.
So what is the purpose of using them in your application? Reason I ask is that at one location that is a 6+1, we are making a new laundromat (the building was originally constructed to be one 20 years ago - but the owner decided last minute to put in a tanning salon). Was it that you needed different temperatures for each application (but you could use a mixing valve for that...)? I may be looking into doing something creative for the laundromat, as it will be packed with washers and have very little space for an "equipment room".
Rudy,2Biz....I love your setup.
In studying tankless hydronic heating....I found a website that raised concerns about reliability. It seems some contractors have had problems since most units were NOT made for a 50% duty cycle.
Although my old RayPaks send 20+% up the stack.....they are indeed RELIABLE. It wouldn't take much to have my floor heat go out on a crazy winter weekend and ruin the cost savings from an efficient system.
How do you feel about reliability?
Also...
Here in PA, I'm told that ASME is required when used in a hydronic system. With Domestic Hot Water....not so as long as the input is less than 200K BTU's. I also have been told (does anyone know for sure?), that daisy chaining 199K BTU units does NOT trigger the ASME requirement.
When does the ASME requirement take hold? I'd hate to have a sweet system like 2Biz's....and then be told to rip it out because it doesn't meet code.
The rules for PA seem to match that of Colorado... ASME is required on any hydronic heating system, but not on domestic water heat. I have seen one car wash that had a floor heat system installed by a car wash distributor in this area where the state inspector did make the owner tear out a new Paloma tankless floor heat system and have a local heating contractor install a regular boiler instead. The same rules also apply for the btu rating, which is why there are so many manufacturers offering a 199,900 btu/hr rating and controllers to run several in parrallel. It would be cheaper to have larger units, but the gov't doesn't figure that matters I guess - just spend more money going around the red tape and they are fine with that...In studying tankless hydronic heating....I found a website that raised concerns about reliability. It seems some contractors have had problems since most units were NOT made for a 50% duty cycle.
Although my old RayPaks send 20+% up the stack.....they are indeed RELIABLE. It wouldn't take much to have my floor heat go out on a crazy winter weekend and ruin the cost savings from an efficient system.
How do you feel about reliability?
Also...
Here in PA, I'm told that ASME is required when used in a hydronic system. With Domestic Hot Water....not so as long as the input is less than 200K BTU's. I also have been told (does anyone know for sure?), that daisy chaining 199K BTU units does NOT trigger the ASME requirement.
When does the ASME requirement take hold? I'd hate to have a sweet system like 2Biz's....and then be told to rip it out because it doesn't meet code.