Hot water to SS bays

[Reds]

I currently have 2 commercial hot water heaters feeding my SS pump stand. When I am busy (during the winter) they cannot keep up. When I am slow the water sits in the reservoir and will often get cold before it is used. I am considering installing on-demand hot water heaters. At what point in the water line should they be located? I was planning on putting one in the line that feeds each individual bay between the pump stand reservoir and the pump. I would mount them on the wall right behind the pump stand. That's a low pressure line that feeds the pump. Does anyone else have them in this same location? Or do you put them before the reservoir? If they are before the reservoir do you have any issue with the water cooling down in the reservoir before it gets sent to the bays? I have an issue with customers coming in early in the morning or right after a dead period. The first few in get cold water that has been sitting in the reservoir. The next customers get hot waterafter the heaters recharge the reservoir. I only have 2 SS bays. Do I need two heaters? Any suggestions would be helpfull.

 

[Bubbles Galore]

I thought I heard somewhere that you basically needed one on demand heater per SS bay that you had. I might be wrong though. Would something like this be cheaper in the long run?

 

[MEP001]

There is a Paloma model that is big enough to feed two SS bays by itself, but using it "on demand" to feed the pumps directly would require some changes.

 

[Dirtychuck]

I have one Paloma PH24 per bay. It feeds a small reservoir then goes to pump inlet.

I think that one Paloma could be able to feed two bays, and that is my backup plan in case one fails, but I've never tried that yet... Even on coldest day with thermostat in middle between cold and hot, water gets pretty warm with one paloma per bay.

My reservoir is about 2 gallons for each bay--at 4 gpm flow the first few seconds is cool water, but it heats up pretty fast.

If I had to do it over again, I'd buy the higher efficiency units that can be vented with PVC instead of B-vent. Cheaper to install and more efficient. Also, since combustion air comes from outside, you don't need a vent in equipment room for combustion air--so not as much heat required for equipment room to keep from freezing.

 

[mjwalsh]

Alternative

Reds,

If you put in a tiny recirculating line that will thermostatically turn on as needed you would solve your customers not getting the warm water. The low cost recirculationg brass or stainless pumps that work so the water doesn't have to run excessively to warm up in the morning for residential sinks & showers are what I am referring to. That should take of the warmth issue.

If you thoroughly insulate your tanks & piping you could possibly achieve even better efficiency than the Paloma style heaters. The efficiency of your hot water heaters would be a factor. Our choice at our laundry car wash are modular sequentially fired 90 plus efficient boilers circlated through heat exchangers inside of super insulated stainless steel tanks. Some study or verification of flow rates should be done to protect the boilers from flow problems. You probably already use soft water which will prevent lime buildup.

 

[MEP001]

One Paloma PH24 can heat enough water for two bays, but it can't directly flow enough water for two. One PH28 can flow 7 GPM and heat that flow to 140?. I have set up a 4-bay wash with two PH24 Palomas and managed to get them adjusted to a good temp, but it was impossible to keep it consistent.

 

[MikeV]

I use 2 Takagi's that feed the 30 gal reservoir to heat all the high pressure water for 5 bays plus the presoak for the auto. Been doing this for over 5 years and have never run out of hot water.

 

[mjwalsh]

One Paloma PH24 can heat enough water for two bays, but it can't directly flow enough water for two. One PH28 can flow 7 GPM and heat that flow to 140?. I have set up a 4-bay wash with two PH24 Palomas and managed to get them adjusted to a good temp, but it was impossible to keep it consistent.

Mep001,

Have you ever thought about setting up a PID loop with one of your PLCs? With a fairly low cost Belimo proportioning valve between your two units' outputs it seems like the water temp could be perfect----not overtemping or undertemping the customer.

This is what we are hoping to do with our coming soon Dog Wash water temp----if some well meaning people do not unwittingly undermine what we are trying to accomplish.

 

[ToFarGone20]

Rise???

I don't care what they say they will flow at what temp...you really need to find out what temp the water is comming in at before it hits the machine. Of course they will flow less the farther they have to bring the water up to temp. I have 5 Rinnai C53's and I run 6 self-serve car bays and two big truck bays with them. If you are worried about running out just install a 10 gallon holding tank to stay ahead of things. Thats what I did ( I also put an inch and a half of insulation around it) and it works fine.

These tankless units are fantasicly simple when you get into it BUT make sure you buy from a company that has good customer service. If you are like me you will have hundreds of questions about things along the way...Rinnai was able to answer most all of them for me. I have a friend that is using Takagi and he seems to have good luck with them as well.

With two bays to feed this is a no brainer, and you are very wise for investigating this option

A.J.

 

[JMMUSTANG]

This is somewhat off the question but how many of you turned off the water heater altogether last year due to heating cost?

 

[Jeff_L]

I'm not an expert on this, but has anyone taken into account the size of your gas line and the volume which comes through it? I would think the tankless heaters need a certain amount of gas and pressure to keep them running. If you had a number of them all fired up at the same time, would you have enough gas pressure to keep them turned on?

May be a moot point, but thought I'd bring that up for discussion. I have no idea how to measure this or prove a theory, but it might be something to think about as well.

 

[I.B. Washincars]

This is somewhat off the question but how many of you turned off the water heater altogether last year due to heating cost?

I turn mine off every summer.

 

[ToFarGone20]

Gas

You are right about the gas...I had to put regulators on anything that used gas in my work room. The utility company had to come put in a different regulator on their end also.

 

[wagsnwheels]

Now thats a good question. I didn't even turn on the water heater last year. Being new to the business I am wondering if I should rethink that this winter to attract more customers?

 

[Bubbles Galore]

I had quite a few positive comments last winter about our hot water. You can definitely tell when the gun heats up that the water coming out is nice and hot.

 

[Waxman]

I keep my hot water on all year, feeding both SS bays as well as my IBA presoaks. However, I just installed a timer on my Raypak that heats wash water. Now the furnace shuts down at 8pm and comes back on at 7am.

My hot water storage tank holds plenty to handle my overnite business.

Can't wait to see the savings in doing this!

 

[Mel(NC)]

I have had my Paloma water heaters off since June. I will have to cut them back on in a few weeks. The Palomas are amazingly reliable. My units were made in 1983 and except for having to replace an occasional daiphram, run without a problem.

I have one per bay and mine also run into 2 gallon reservoirs. I can tell you one problem with this configuration. I would like to have hot water for soap and wax cycles and cold for the rinse. However, it takes 30 seconds or so to drain the reservoir so the customer has already switched to a different cycle before the right temperature water gets to the bay.

 

[MEP001]

I don't care what they say they will flow at what temp...you really need to find out what temp the water is comming in at before it hits the machine. Of course they will flow less the farther they have to bring the water up to temp. I have 5 Rinnai C53's and I run 6 self-serve car bays and two big truck bays with them.

The Rinnai heaters have a restrictor that slows the flow so it can heat the water to your set temperature. Palomas do not - the PH24 has a rating at which it can heat 2 GPM of water at a certain degree of rise, but the PH28 states simply that it can heat 6 GPM to 140?.

 

[MEP001]

Mep001,

Have you ever thought about setting up a PID loop with one of your PLCs? With a fairly low cost Belimo proportioning valve between your two units' outputs it seems like the water temp could be perfect----not overtemping or undertemping the customer.

Not at the time, though I did try to talk him into a simple temperature regulating valve. He didn't want to spend the money, and he has since sold the wash.