40 by 60 radiant floor heat

[sprntpshr]

After reading thru all the good advice here, in 2010 I had my 40' x 60' shop built with in floor radiant heating. It has taken some time to get the heating system up and running (long story) but within the last couple of weeks it has been on and running. Did alot of the work myself with some hired in help from time to time.
Still a few kinks to work out with overall control strategy and loop pump sizing.

Of course its spring now, but Hey, that means it will be all dialed in for this winter.

Some quick specs: 13 runs of .5" pex @ 300' each, Emmeti manifolds, Viessmann nat gas boiler, 60 Gal buffer/storage tank, primary/secondary pump loop. 5" concrete slab, foam board insulated on the exterior and underneath. The building was well insulated when built, I just forget what the specs are at the moment.

Edit: Floors 2in Greengaurd foam-board, walls Fiberglas air barrier backed R17, ceiling same only thicker R22

Performance so far has been good but the truth will come out once I get the first gas bill..

 

[jvitez]

Very nice setup! Congrats!

What's the efficiency rating of the Viessmann? I don't think I've ever seen anyone use one on GJ for shop/garage heating.

 

[sprntpshr]

Thanks for the kudos.. The boiler is a Viessmann Vitogas 050 ECV. The AFUE is 83.1% per the boiler spec sheet. Power vented out thru the wall using Z-Flex stainless venting.

Kinda fell into finding a Viessmann boiler, heard that one was being removed after an install that went south and it got repossessed about 6 months later.

Since it was used it could not be installed again as "new", that really wasn't a problem for me.

 

[jack stand]

Real nice, you're all set for next winter! With your storage tank do you set your limits farther apart? That is for longer boiler operation at farther apart intervals, (charging the tank) for efficiency. Your radiant should be happy with about 110* water, leaving long in between "burn" times for your boiler with that storage.

 

[sprntpshr]

Real nice, you're all set for next winter! With your storage tank do you set your limits farther apart? That is for longer boiler operation at farther apart intervals, (charging the tank) for efficiency. Your radiant should be happy with about 110* water, leaving long in between "burn" times for your boiler with that storage.

Thanks, Ready for next winter is the plan. The operating limit @ boiler set to 145F with the tank aquastat set to cut in @ 125F. Currently the Delta T thru the boiler is a little high due to primary pump issues (solved shortly).
The goal is for the boiler to run a longer cycle to maintain tank temperature to reduce short cycling. I don't like boilers short cycling.
Currently the radiant loop temperature is set for supply design of 80F and a return of 50F. Once the slab is up to temp. The boiler runs for about 8 minutes an hour with an ambient of 52F, I don't like it too warm in the shop.

I would describe the system as a work in progress. The designer/contractor of the system bailed once he got his advance, just as the tubing was placed before the pour.
He left alot of problems and unfinished work, as a result I have had to finish it up myself with some help from friends in the business.

 

[sprntpshr]

A quick update is in order since it has been awhile.

The boiler short cycling on the hi-limit was caused by the primary pump impeller plugged with leaves and grass.? Further investigation revealed that the boiler had sat in the overgrown backyard of the original instal for a few months prior to my acquisition. Furry little critters.....

Even with the boiler issues and heating loop flow problems, for Feb & March 2013 the natural gas bill was a total of $30 higher for both. Mind you it was one of the warmer winters here. This year not so much.

The boiler was started on Dec 1 2013 and has worked well, more fine tuning along with a temperature control to moderate the system during the wild temperature swings we have been getting. The wiring is still a bit messy as I have yet to finalize it, hence nothing is clipped up yet.

Overall, I am very happy with its operation this year, real nice to walk the 400 ft from the house into the shop at 54F from -20F outside.

More to follow when the bill comes in

 

[pstnbly]

Looks good, I would suggest a Spirovent though as without good oxygen removal you run the risk of hydrolocking 1 or more of you floor loops.

 

[sprntpshr]

I likely will add a Spirovent in the summer once the system has been shut down. During start up, the loops were pressure filled by jet pump and manually purged at couple of high points to remove air.

It was 54F in the shop today and the boiler cycled once during the afternoon with the thermostat set for 52F. That is plenty hot for me when working in there. We do get a bit of solar gain from 2 south facing windows.

 

[rburke65]

Can I ask what part of the globe you reside? Nice set up.

 

[sprntpshr]

Can I ask what part of the globe you reside? Nice set up.

Thank you, always wanted a decent heated shop. It took awhile but it sure is nice.

Near a village named the same as yours, only due north across the lake from Erie PA in Ontario.

It has been like a normal winter here, high of 15F today and was a good day to cut firewood for the house

 

[rburke65]

That is a nice size shop you have there! Great size....with heat! The only thing bad is the bills, but ya can't have it all, I guess. I have my pex in and my manifold connected....the shop is finished. Looking to finish the system soon.

 

[jack stand]

Thanks, Ready for next winter is the plan.Currently the radiant loop temperature is set for supply design of 80F and a return of 50F..

Do you have a cold water protection valve on your returning (to the boiler)water. I know that on wood boilers that this is important to the boilers life. My wood boiler specs. a 20* differential on water returning to the boiler. I would think that it is the same on all boilers, reguardless of the fuel.
Sounds like you're nice and cozy in your new shop

 

[sprntpshr]

Thank you for the question, jack stand.

Yes, there is low water return temp protection. There is an aqua-stat in the boiler that turns circ pump off when the return to the boiler is below 98F. You try to keep the boiler above flue gas condensation point, about 94F.

When the boiler is firing and gets to 110F the aquastat closes and starts the pump. It is a handy feature already built in to the Viessmann.

I did instal a bypass leg on the boiler loop circuit with a ball valve to adjust the return temperature but so far haven't needed it since the storage tank acts as a buffer between the boiler and the floor loop. At some point I may outline the system and how it operates for the GJ board readers.

It is really nice to go into the shop, take off the parka and sit down at the bench not freezing fingers and ears. Spent many years out on the driveway battling snow, rain, loosing tools in the dirt.

 

[GYPSY400]

Edit: Floors 2in Greengaurd foam-board, walls Fiberglas air barrier backed R17, ceiling same only thicker R22

Performance so far has been good but the truth will come out once I get the first gas bill..

If you find your gas bills high I would suggest more insulation in the ceiling if you have room.. I have R20 walls and double layer in the ceiling - so R40. R22 in a ceiling doesn't seem like enough.



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[Snowman87]

Curious on your heating bill costs. Thinking about building a similar sized shed and wondering if I want to try keeping it heated all the time or whether I should go with a weekend warrior approach.

 

[sprntpshr]

Curious on your heating bill costs. Thinking about building a similar sized shed and wondering if I want to try keeping it heated all the time or whether I should go with a weekend warrior approach.

I am curious about the heating costs as well, since the system hasn't run a full season. Should have something useful for comparison by the end of this month. Our gas bills come in around the 20th of the month and then will have about 2 months of usage.

The heat is on all the time, since I don't think I would really save anything by raising and lowering the temperature since I tend to be in there pretty much everyday.

So far a rough estimate was $160 for startup and all of Dec & couple of days in Jan '14. That is a constant 52F thru some of the coldest weather in 20 yrs here. Todays high was 14F, last year 35F. Not to bad I think for a 40 by 60.

Insulation wise, will dig out the plan to see what R value for the ceiling was spec, was just going off memory for the numbers above.
We are in Southern Ontario so the insulation requirements maybe different in other areas.

 

[loweredd]

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