Latest Discussions : HVAC


10:53AM | 01/15/05
Member Since: 07/31/00
59 lifetime posts
Sorry for the length of this note, thought some of the stuff might be helpful to know and/or for others if they are interested in a hydronic radiant heat system. My big issue is no hot water coming out of my faucets. Been this way for a week now, and I’m dying for a good hot shower in my own shower. (Others are dying for me to have one too….) Also, been awhile since I’ve been on the site, but some of the stuff below is what we/I’ve been working on the last few years……

We live in a reconstructed and modified timber frame barn. We have a hydronic heating system with a Viessman boiler, An Expansion Tank at the Boiler, Triangle Tube Smart50 indirect water heater, Argo 4-zone priority circulating pump management and Taco 007-F50 circulating pumps. We use pex installed inside a 6” slab along the entire floor of the house and the attached three car garage. (Most of our pets stay in the garage and so we keep a low level of heat in there for them. Not bad for us as a workshop either!) The system has been installed about two years. We keep the slab at a minimum of 60 degrees year round. We have no actual hot water heater, only the indirect hot water heater. All are installed in a 6’ high space under the end quarter of the barn. My husband calls it the mother-in-law’s quarters, but it’s really a space under the suspended slab that we were able to have due to the grade of the land.

Love the system! Fantastic even heat. Have to keep the floors clean as the dust floats up to the loft area a lot! No need for heat on the second floor or in the loft. It stays toasty up there during the winter. Our average bill for propane is about $105.00 per month. Perhaps a bit more with recent gas price increases. Electric including very cool air in summer averages about $75 per month. 3900 square feet, 3 bedrooms, 2 baths.

We had 13 of us in the barn for the holidays for about 2-3 weeks. 7 adults and 6 kids. Usually just the two of us, so all those folks may have put some extra stress on our hot water system. We finished unpacking our stuff around the barn, (we’re still in the process of completing everything) As a result, we had LOTS of washing and cleaning and showering.

Last Sunday everyone was gone. After starting a load of laundry, and following my husband’s shower, I found I had no hot water. We NEVER run out of hot water with the system we have. No matter HOW much is going on.

The temperatures were high outside, but we are pretty sure the heat was/is still working – we have a closed system of tubing in a 6” slab of concrete. The Viessman is cycling off and on. We replaced cartridge on Taco 007-f50 pump for priority zone 1 pump to hot water heater. There did not appear to be water flowing to hot water tank -- outside tank, and the pump appeared to be getting way over hot, making noise and hammering. Copper pipe was hot, but appeared to be only heat transfer from hot pump rather than from fluid in it. Water came out of the lower drain valve of the hot water heater, but did not refill. Left the hot water taps turned on each time we’ve worked on the system to be sure the system didn’t run dry. Couldn’t make it work and needed to do some more research, so last Sunday, we turned off the circulating pumps at the switch, but the boiler stayed on. Did the research, lived for a week without running hot water – ugh! My husband and I still love each other; not sure our employees feel the same about us, after a week of us taking sponge baths of heated water!

Today, after changing the cartridge, water was available in the lower drain valve. The circulating pump no longer makes a knocking noise. I released air and left it open in the valve on the top of the Smart50 water heater. Another pump is making some knocking noises – just a few, though for zone 3. Zone 2 is currently capped off and zone 4 is for the main house. Zone 3 is for garage and has less flow.

The fluid that came out of the drain system was very dark in color – found a bit of space in copper pipe sweat join that might have a minor leak near the water heater. Also had a minor link at a fitting (screw tight) for the garage zone. Tightened it with a wrench and it has stopped leaking. The circulating pump filter assembly was dry when I pulled it out after trying to get everything circulating. Air/steam did come out of the piping between the boiler as the circulating system came back on.


1) It’s been two hours since we changed the cartridge. Still have no hot water. Could we have another problem with the indirect water heater? Or could I have another problem?

2) Could the color in the fluid be from a chemical mixed with the system to retard freezing? Could the fluid be oxygenating? Is that a word?

3) I can sweat the pipes and repair the minor leak in the solder joint near the drain on the outlet back to the system without any problem, but should I do it that close to the Smart50 or could it damage a “dipping stick” in it? Or is that only on the cold water inlet on the top not the drain area?

Any ideas, questions, thoughts, etc?



03:31AM | 01/16/05
Member Since: 03/01/03
22 lifetime posts
You have a top of the line system IMOA. I woiuld call someone in to take a look at it- the installer if you can find him. I'm guessing the "dark water" came out of the boiler loop lines?? It could have an anti-freeze additive in it. Air caught in the indirect??? I really think I would be calling someone......


07:42AM | 01/16/05
Member Since: 07/31/00
59 lifetime posts
Many thanks for the posts, guys. And also to Lonnie, The Plumber for his frank assessment. Also, HKenstenholz, MANY thanks for the referral website. It really helped bring a lot of my other research together to help me better understand the overall system and how it works together. I'm pretty handy and learn pretty well, but some stuff wasn't making sense. Got the troubleshooting book, cause it will help too!

The Pex within the slab is red. It has a mix in it and is totally self contained with a separate manifold. So I think, based on what I've learned from stuff I've read today is that the water circulating in my copper tubes that link with the different pieces such as the indirect water heater and the pumps and heat exchanger for the pex for my other two heating zones is probably the culprit area. That's where I identified two leaks. One into the primary 1-1/4" copper to zone 3. It's been tightened and is no longer leaking. The other was at the bottom of the drain for the boiler return on the indirect water heater. There's a blown part of the solder joint. As I read through more stuff last night, I realized that the dipping stick is probably at the top not at the drain at the bottom area. MAPP gas here I come. Will get the remainder of the fluid drained out and will get that joint repaired.

Since I looked at the referral site this morning, I expect that the pressure valve reading O(zero) has a great deal to do with the lack of flow of water within the system. So, once I get the leaks repaired, I'll need to refill the boiler system. The calculations to do that will be lots simpler than for other systems since the circuit is pretty small and just in the Mother In Law's quarters since the other loops are self contained.

It's a glorious system design. Our contractor used a firm out of state. Then our contractor departed for the netherlands. He apparantly neglected to pay a number of the subs either full or remaining balances. I know, another of those gross stories.....We kept the barn from going into foreclosure, we've gone to court with our certified checks showing we paid, but.....can't bring in the original guys to talk about the system... Also, have been unable to find local (Chapel Hill/Durham NC) folks that we could hire for annual service checks. If anyone can refer me to someone I'd love to talk with them.

Thanks again. Hope to be showering by morning..... Have temps in the 20's and some snow flurries this morning, but our indoor temp is still in the high 60's. That's at least 1 week without heat and the slab and system have still kept us toasty. We'd had some warm weather during the days, but at least 12 hours/day for a week were well below 40 degrees. That's why I love this heat. It's also great for my allergies, and keeping it at 60 during the summer ensures we don't get mildew or condensation on the pad/slab. Though it is kind of funny to have the boiler on when it's 90 degrees outside.....



12:15AM | 01/15/14
I have a closed loop system with three zones in a 1400 sq foot slab. Installed in 2011, Polaris boiler.
If the zones do not call for heat I can't get any hot water from the faucets in the house. If I raise the thermostat in one of the zones hot water to faucets comes back.

Any ideas on what's going on?

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