Boiler sizing

[GoBuckeyes]

At one of my locations my Raypak Hot water boiler and holding tank are ready for the scrap yard. The wash has six bays and they’re set up at 4 gpm. Conceivably that is 24 gallons per minute of hot water needed and in Cleveland our incoming water can be as low as 40°. We typically set our hot water between 110 and 115° so that’s a rise of 70 to 75°. Is there a rule of thumb for figuring how many minutes out of an hour a pump may be on high pressure? This is by far our slowest wash so I’m thinking maybe 25%.
I’m thinking a smaller Phoenix HTP maybe the way to go. Just recently I had to replace a 120gal Storage tank at another wash and the tank alone was $1100 not including any fittings.

 

[Eric H]

I was going to recommend a Phoenix! I wasn't able to fit their unit at my last remodel so I have a 80 gallon storage tank attached to a Rinnai tankless heater with a circulator pump. I have the tankless set to 135 degrees and then a mixing valve coming off of the storage tank to bring the temp down to 120 to supply the pumps. This gives me a little extra how water capacity and recovery time should be shorter.
Ideally I would have used a Phoenix but I'm satisfied with my setup. My only concern might be, will the Tank outlast the burner section? (or vise-versa?) With my setup I only need to replace the failed component.

 

[GoBuckeyes]

Eric,
How many btu’s is the Rinnai and how many bays is that servicing?
The Phoenix have been on my radar ever since 2Biz mentioned them years ago. The timing never happens to be right for me though.
Like I mentioned before this is our slowest wash so I’d like to spend the least amount possible. Although, By the time I buy a storage tank, the correct size circulating pump, the heater and all the other fittings it may not be much less than the Phoenix.

 

[Eric H]

This is a busy 2 bay SS with 2 Razors. Rinnai is 199,999 BTU. To be honest I don't think I ever did the calculations on the tankless sizing. My other sites each have 2 199,999 BTU Navien tankless units. Those sites are a 4 bay SS and 3 bay SS/2 IBA. I don;t think I have ever had an issue with running out of hot water.

 

[tdlconceptsllc]

A 119 gallon 199btu standard simple commercial gas heater would be a plenty for a 6 bay with those setpoints if you want "the simple route"

I have a CU series Rinnai tankless at a 10 bay SS location with a closed loop with circulator pump and a stainless Indirect storage tank so I suppose to get descent life out of the tankless. I run my mixing valve at 119/120. It's several different setups to do so depending,on how much money you want to spend and space you have and if you want to stay in the 199btu loophole for inspectors. I have heard nothing but good about the HTP heaters also. Laundrymats have them and they use more water than we do.

 

[tdlconceptsllc]

This is a busy 2 bay SS with 2 Razors. Rinnai is 199,999 BTU. To be honest I don't think I ever did the calculations on the tankless sizing. My other sites each have 2 199,999 BTU Navien tankless units. Those sites are a 4 bay SS and 3 bay SS/2 IBA. I don;t think I have ever had an issue with running out of hot water.

Eric are you heating High Pressure rinse water also or just Lo pressure functions just curious

 

[Eric H]

Eric are you heating High Pressure rinse water also or just Lo pressure functions just curious

In my Razors I heat the Presoak, and Hot wax.
For the SS bays I heat Tire, Presoak, HP Soap, FB, HP wax, and HP clearCoat all year. My HP Rinse switches automatically to hot water when the temp is below 27 degrees. I use the 2nd output on the weepmizer to operate a contactor to make that changover.

 

[MEP001]

I have a CU series Rinnai tankless at a 10 bay SS location with a closed loop with circulator pump and a stainless Indirect storage tank so I suppose to get descent life out of the tankless.

I want to do the same thing - do you remember what you paid for the tank? I've been shopping for some time, and the stainless tank alone usually costs more than a Phoenix HTP unit.

 

[I.B. Washincars]

I have a 80 gallon storage tank attached to a Rinnai tankless heater with a circulator pump.

Doesn't that kind of defeat the purpose of a tankless? Seems like a tank style heater would be more practical and save a lot of space at the same time.

 

[tdlconceptsllc]

I want to do the same thing - do you remember what you paid for the tank? I've been shopping for some time, and the stainless tank alone usually costs more than a Phoenix HTP unit.

Mep I bought the indirect from Ferguson under my account for like $1,600 or so has stainless heat exchanger coil inside 80 gallon. I could pull the invoice if you really need to know exact

 

[tdlconceptsllc]

Doesn't that kind of defeat the purpose of a tankless? Seems like a tank style heater would be more practical and save a lot of space at the same time.

Well its how extensive and industrial you want to build it in all honesty and I like simple tank styles myself but then you have a (Indirect style tank with a heat exchanger coil inside the tank that exchanges the heat to the surrounding water).

Every wash is different for what you need I think. Do you want a single big exhaust metal flue pipe through the roof with a 80% tank, or a 98% HTP setup you have to have a fresh air and exhaust PVC seperate or a Tankless setup like mine with fresh air and exhaust straight through the wall with no roof punctures. It's so many different Pros & Cons honestly. My setup is very efficient and quick recovery on NG gas vs a convential tank style heater and if the tankless goes out I can swap the entire thing in 15mins. I never have fresh water constantly going through the heater either city water can make a tankless scale up quickly also the closed loop way slows that down also.

 

[tdlconceptsllc]

I want to do the same thing - do you remember what you paid for the tank? I've been shopping for some time, and the stainless tank alone usually costs more than a Phoenix HTP unit.

Here's a link for exactly what I have Mep

633-600-003 - Weil-McLain 633-600-003 - Aqua-Plus 85 Pewter Indirect Water Heater

Weil-McLain 633-600-003 - Aqua-Plus 85 Pewter Indirect Water Heater

www.supplyhouse.com

 

[soapy]

I have 2 early versions of the HTP water heaters, 110 gallon and 199,000 BTU. They will raise water temp 5 degrees per minute on these units when I fill a 55 gallon barrel with hot water. I run 4 SS bays and 2 IBA touchless units and never lack for hot water. Both units are 20+ years old.

 

[MEP001]

Doesn't that kind of defeat the purpose of a tankless?

Partly yes since there's heat loss from storage you don't have from the on-demand, but remember boilers are 80% efficient at best while most tankless heaters are 98%. Also most of us won't have to worry about the intrusion of boiler inspectors if we stay below 200k BTU.

 

[MEP001]

Here's a link for exactly what I have Mep

633-600-003 - Weil-McLain 633-600-003 - Aqua-Plus 85 Pewter Indirect Water Heater

Weil-McLain 633-600-003 - Aqua-Plus 85 Pewter Indirect Water Heater

www.supplyhouse.com

Thanks, that's not bad on price at all, but I want to stay below the 200k BTU threshold.

 

[GoBuckeyes]

TDL,
Thanks for all the info and the pic. Couple of questions...what are the specs on that circulating pump? Also, all your piping looks like 1” including your mixing valve. Those 1” mixing valves say they will only flow 16gpm. How do you run 10 bays with only 16gpm? I take it they’re gravity fed not pressure fed.