How many BTU's is your boiler per bay?

[piperken]

this is a call out to all car wash owners as to how big is your boiler for floor heating using pex or steel in floor. we have a 3 bay wash using a weil and mclein 105000 BTU boiler with pex in the floor. Im wondering if it is a bit underpowered. HOW BIG IS YOUR BOILER IN OUTPUT per bay or total for a 3 bay wash??????????? this may give me the answer as to whether our boiler is under sized. Ive already seen 2 washes one with a 375000 BTUS output and he told me it was a little too big for 3 bays and another with a 300000 BTU boiler , 3 bays and both being pex in the floor and this guy had no problem getting rid of ice on those -25 mornings. cheers

 

[OurTown]

627K BTU input/514K BTU output for 5 bays plus some aprons. About 3,300 SQ feet of outside heated concrete.

 

[piperken]

627K BTU input/514K BTU output for 5 bays plus some aprons. About 3,300 SQ feet of outside heated concrete.

your 3 times the output. do you have any problems with ice build up on the floor?

 

[OurTown]

your 3 times the output. do you have any problems with ice build up on the floor?

Yes we do if the slab stat is set below 50F and its windy, overcast and below 10F outside.

 

[soapy]

You also need to check the zone you live in for cold. Huron valley sales used to have a map that you could figure your needs based on zone and square feet. Rough rule of thumb has been 100,000 btu per bay here in Idaho. It is under I've prevention sizing on the Huron valley website. Average ss bay is around 500 square feet plus heated aprons if you have them. Minimum would be around 75,000 btu per bay it looks like.

 

[piperken]

You also need to check the zone you live in for cold. Huron valley sales used to have a map that you could figure your needs based on zone and square feet. Rough rule of thumb has been 100,000 btu per bay here in Idaho.

We are in the great lakes region near georgian bay and what im seeing so far is just that, 100000 BTU per bay which would mean i need a bigger boiler.

 

[PaulLovesJamie]

199,000 btu for 5 bays self serve. 95% efficient. Modulating.

As Soapy indicates, its not as simple as raw btu capability though. My old boiler was rated at 80% efficient, the new one is 95. But the old 400,000 unit was only producing at about 60% efficiency.
Running longer and modulating can reduce the peak btu requirements, as well as improve efficiency.
The fluid in your pex effects how many of those btu's will make it into the floor.
How the pex is installed will effect what you need - how closely are the lines installed, and how deep?
Wind will effect how much of the heat stays in the floor.
Do you lose a lot of heat melting snow that gets "dumped" on your floors, that can chew up all available btus.
What temp you run the boiler at makes a difference
What temp you run the fluid to the bays at makes a difference
How long it runs makes a difference

Another question I'd ask is, do you really need to be open at -25 degrees? I'm not saying you dont, but in my case a little bit of analysis showed that below 10 degrees, unless there is salt on the roads, sunshine, saturday, and no wind, I'm losing more money by staying open than I will if I close. No doubt thats market dependent, but I'm not the only one closing when it gets cold.

FYI I'd bet that 105 kbtu isnt enough for 3 bays at -25 up there north of the GTA - and I'm guessing you also have a steady wind. But adding btus *might* not be necessary. Or it might be the only way Good questions, keep digging.

 

[MudMoney]

Piperken

I've got a 3 bay ss,they are 48' long & 15 wide. I use a weil-mclain that is rated 366,00 btu input natural gas.I ve never ran out of hot water on my best days. Boiler is 20 years old too.

 

[celica]

piperken

As a fellow Ontarian with similar weather I can tell you what I have. I've also got a weil-mclain, but with 175,000 btu for 4 bays. It's 80% efficient so I have 140k net. Heating your floor is incredibly expensive as you know. I keep mine set at 100 degrees for most of the winter. On those -25 days, I simply turn up the temperature accordingly. What temp is your heat set at ? At -25 you can keep a floor perfectly clear but at a crazy cost.

 

[bert79]

We replaced a a 34 year old raypack with a 279,000btu lochinvar wall mounted boiler. It heats the floor, trough and equipment room. We have a 3 bay ss and one IBA bay with doors. This was installed by a plumbing company that specializes in hydronic heating. They sized the system for our location on the west side of Michigan. We have been very happy with the performance and the utility bills. Just got done with the first winter and we are happy.

 

[2Biz]

To add what PLJ highlighted...I think we both upgraded to a 199K High Efficiency Demand Heater about the same time. I couldn't be any happier with the install. I feel its much better to monitor the return glycol temp with a 15° differential for optimum control over slab temps...You'll have a lot more control over each bay by tweaking flow and adjusting the return aquastat and demand heater output temp. If you go with a demand style heater, you'll need a primary/secondary plumbing configuration so you'll need a pumps or pumps to feed the heater. Once I got the system set up and tweaked, I haven't made a single adjustment since, even down to -16°.

I do have mixed feelings about what temp to close down. I only close down all 4 bays below zero now but leave the floor heat on. I've stayed open to -16° with ice free open air bay floors! But haven't figured out how to keep the ice off the walls without spending big bucks on doors! The past few years, I close down 2-3 bays when temps reach 0-10° or below, mainly to save on weep water...Its rare I close down all the bays. The other two washes in town close down below 32°...I pick up more "Long Time" customers by going the extra mile....

 

[wash4me]

We have 240,000 95% efficient but it also does the hot water out of the same boiler for 6 self serve and 1 auto and all of them have about 4 feet apron in front and back. This is enough for all but the below 10 degree and below days. In my opinion you'd be better off keeping what you have and it will simply run wide open when it gets real cold but immediately on warmer days it will be ready. It's easier on the boiler to run wide open for a long time than it is to cycle. Also if it gets to cold you won't have much business anyway so if it's going to be an extended period of time we can shut down the glycol flow on a couple bays and that leaves more heat for the other bays.