Finally bringing heat to the shop - questions

[hartkem]

I have heated my house with my EKO 40 for the last two winters with no problems. I have 500 gallons pressurized storage in my basement and the EKO is in a outbuilding 150' from the house. I have 1 1/4 thermopex underground to the house. I built a 30x50 stick built shop last summer and just finished installing air conditioning. I used a Goodman air handler and heat pump condenser in the shop. I have 1" thermopex from the EKO to the shop which is 100' away. The lines going to the shop are T'd into the supply line and return lines near the boiler. I plan to use a water/air heat exchanger in the shop duct work. I will use a small three speed taco pump with integral flow check for the shop loop. My question is will I get flow through the shop loop with the main boiler pump running and the shop pump off? I don't want gost flows through that loop when I'm heating the house only. I'm not sure if the integral flow check will stop this flow or if I need a zone valve. The shop is about 5' higher than the boiler shack. Attached is a picture of inside of shop and new air handler.

 

[ewdudley]

Can't tell from your description how the shop loop is situated relative to the main loop or relative to the boiler-to-storage loop.

From what I've been able to glean from studying the Taco pump curves, the IFC curves are about 1 psi lower than the non-IFC curves while the pump is pumping. Also it seems to me that it takes a significant amount of extra pressure to pop the IFC open. So if your problem is purely thermsiphon pressure I would think the IFC will easily prevent any ghost flow, as they are designed to.

But if some other circuit is pumping in parallel with the shop circuit then that pump could pop the IFC and you would see some parallel flow.

 

[hartkem]

I drew this up quickly. Hope this helps show my piping.

 

[ewdudley]

Yes that helps a lot!

With 150' from boiler to basement storage the shop circulator would pull most of its flow through the boiler the way it's drawn. This wouldn't a problem if the boiler is running and supplying plenty of hot water. But don't you have a thermostatic return temperature protection valve at the boiler? A thermostatic return valve would normally close itself when the boiler is not heating and that would enable the shop loop to draw exclusively from storage in the basement.

The boiler-to-storage pump would cause a problem as you suggested in the OP. The IFC would not prevent parallel pumped flow (as opposed to thermsiphon flow) to the shop. The pump would see 300 feet of 1.25" pipe one way and 200 feet of 1" pipe the other way and the flow would split so as to equalize the pressure drop with significant flow going both directions. So it looks like you would need a zone valve to prevent flow to the shop circuit when the shop is not calling for heat.

Also you might need some sort of balancing valve to limit flow to the shop because if too much flow was happy-turning through the shop HX the return temperature to the boiler would rise to the point that the boiler wouldn't be able to run at capacity without overheating.

 

[hartkem]

Thanks Ewdudley! That's exactly what I needed to know. Here is an old pic showing my boiler piping. I do have return water protection. I don't have the shop hooked up yet in this picture but you can see the stubs/ball valves under the shelf which are now connected to the shop loop thermopex. As far as a balancing valve I could slow the flow with one of my ball valves on the stub if that becomes a problem.

 

[Coal Reaper]

hartkem, whats it cost for fiberglass? pipe insulation like that? looks really nice! i have foam on my piping now and would like to put something like you have over thta one day.

 

[maple1]

I found some Knauf here earlier this year. Can't lay my hands on a receipt right now, but it was somewhere in the middle of the $1-$2 per foot range (a buck-something). The joint tape was kinda pricey, but my memory is failing me on that too. Something like $50/roll? I only got one roll & think that will do me. I could be out to lunch on that figure. But it's nice stuff, compared to the ordinary black foam hardware store stuff. I don't think my install job with it looks quite as nice as hartkems though - that's looking real good.

 

[hartkem]

hartkem, whats it cost for fiberglass? pipe insulation like that? looks really nice! i have foam on my piping now and would like to put something like you have over thta one day.

It's been a while now so I don't remember exactly but I bought it locally and remember it was less than $150 to do what you see in the picture.