Best Of
Re: Small shop/storage building
The decision for me would be based on how often I would be working in the shop. Cold concrete floors really drain you energy. If in fact you spend time out their overhead radiant would be a good option. Quiet, clean, faster responding.
The over head radiant tubes heat well, when you are directly under them, not so well when you move to the outside walls, away from their line of site.
FA unit heaters drive me nuts with the fan noise.
hot_rod
Re: Insufficient Domestic Hot Water off Indirect Coil
I would definitely make sure the aquastat settings are as @HVACNUT described. That's the first step. Next step would involve descaling the coil and adding a real thermostatic mixing valve. I prefer the mixing valve from Caleffi that has a thermometer built in to it.
If it was my boiler I would abandon the tankless coil and install an indirect water heater. My customers that have indirect water heaters never complain about running out of hot water or anything else. I can't say the same thing for my customers who have tankless water heaters, combi boilers and heat pump water heaters.
Re: Insufficient Domestic Hot Water off Indirect Coil
Make sure the Economy setting is off in the Hydrostat. Limits at 180 High, 160 Low.
It should definitely have a thermostatic mixing valve.
Baths with a tankless coil need to be drawn slowly.
HVACNUT
Re: Insufficient Domestic Hot Water off Indirect Coil
could be as simple as deliming the coil Assuming the control settings are correct.
hot_rod
Re: Insufficient Domestic Hot Water off Indirect Coil
You may need a low limit aquastat setting of 160 to 180° to get enough hot water out of that; the high limit needs to be set at least 20° higher.
That bypass or mixing valve is not up to code; it must be thermostatic and listed for the application to prevent water at full boiler temperature from getting to the taps, which is a scalding hazard. This will also go a long way to steadying the hot water supply temperature assuming everything else is working properly.
Deliming the coil may also be needed, depending on local water quality and age of the coil.
bburd
Re: Insufficient Domestic Hot Water off Indirect Coil
Hi, That pattern could also be a crossover in the plumbing. Try shutting water off to the coil and opening a hot tap. It should stop running in seconds. If not, there is a crossover to find. 😈
Yours, Larry
Re: Before you swap a component
Pinball machines, jukeboxes and telephone exchanges lived thanks to the contact file. The only tool I needed back in the days.
Re: Piping for New Steam Boiler
Hi @delcrossv. In close inspection of all radiators, found what you had been hinting at all along. See attached. Also the home is just over 4,000 sq ft so crude measure I got given climate zone, gives EDR requirement of around 200k btu. And I used pickup of 1.33 and got 266k btu. But given you suggested a reduced factor despite the older, uninsulated home, I got 230k btu. So that’s about 8% oversized rather than about 8% undersized as I was calculating. Now the rad EDR for those connected is around 180k…but that’s without all the connected radiators and with connected radiators it’s going to be around 200k btu but no pickup added. With conservative pickup of 15% instead of 33% we end up with 230k btu.
On a side note, working on Hartford loop and it’s usually 2 inches below water line. There seems to be confusion online as to where to place it with regards to waterline. 2 inches Below max waterline, or min, or middle…I’m under understanding of 2” below operational or middle of glass gauge????
Noah_1
Re: Piping for New Steam Boiler
Hi @Noah_1! Did you get your EDR by measuring the rads or doing a heat loss? Steam isn't hot water and steam EDR is the connected radiation only, not building heat loss. If you need help calculating EDR off radiator measurements, we can help.
Assuming you have 200k of connected radiation, you don't need to add a pickup factor to your EDR measurements as that's baked into the boiler rating. So using your 200k number you'll be about 1/3 oversized with your 250k boiler, but not grossly so. Your system will cycle on pressure so getting a vaporstat is pretty much a no brainer.
Your boiler I&O manual will spec where the Hartford Loop should be located, but it will be no lower than your LWCO limit (usually). If the manual isn't clear it's 2" below the operating WL- middle of the glass.
If those valves are all through the house, and they work, the regulation is built-in. A little PB Blaster on the valve stem often frees them up. Tunstall may make rebuild kits for these if they're completely fried, but you'll have to contact them.
You'll need to keep the pressure low enough to ensure the valves don't admit more steam than the rad can completely condense. A lot lower than a regular pressuretrol can provide.
You may need to open up the return elbows and remove stuck bafflers if a rad won't heat. It's a common failure mode.
Keep us apprised as things move along! 🙂
