We've been going through a major ordeal with the installation of our new Heatmor 200CSS for the last month. The bulk of the ordeal was hiring some guys to do the install that seemed fine at first (one even owns a Heatmor), but who clearly didn't know what they were doing. It's a long and sordid story that I won't recount here since it's, for the most part, irrelevant now. I hired someone else to undo what they screwed up and we've got heat now. We're not bug-free yet, though, and I was hoping for some insight from the group here in addition to the research my dealer is currently doing.
In a nutshell, our system is a 200CSS on a concrete pad about 65 ft from the house and only slightly downhill. The top of the furnace is probably roughly at the level of the pipes inside the basement under the floor (single story with unheated attic). Our house is close to 100 years old and we have cast iron radiators (about 18 of them, I think). The system was formerly steam with a propane boiler that was costing us a fortune, hence the switch to a wood furnace this fall. This also meant moving the radiators from steam to water which they are capable of since they are the two-pipe design (feed on the top of one end, return on the bottom and parallel paths across through the columns).
First off, we knew we needed to add bleeder valves to the radiators and we fought through that hell. They had screws painted and sealed into the hole where the bleeders would go and it took a LOT of work (heating with a torch, etc) to get those out. Ultimately, they all came out fine with the threads intact and we put little key-turn (with a slotted screw head) bleeders in each one. They seem to work fine since we can bleed off air when the pumps are running and, after some bit of air (if any), water comes out in a steady stream or jet. We also opened the little contraption on the return end near the floor on each radiator and removed the old steam-related condensation trap mechanisms.
The feed into our house is a bit large. When the HVAC guys first looked at our old system, they saw that the head pipe from the old furnace was 2.5" in diameter. It T'ed toward the front and back of the house where the pipes step down fairly quickly to 1" and/or 3/4" pipes that go up into the radiators and out from the radiator returns. They felt they needed to meet that with 2.5" of water volume (this is an issue in serious contention now since in a closed, zero pressure system, I didn't think we had such issues once the system is full and the circulators are running). Whatever the case, the 200CSS has a pair of pumps mounted on its supply that connect to two 1.25" PEX feeds into the basement (that stuff alone was a huge holdup in our install since nobody has fittings, tools, etc., without special order). I thought they were going to combine those 1.25" into one 2.5" source of water right into the main 2.5" cast iron pipe from the radiator system. Instead, they ultimately took the T'ed segment of that 2.5" pipe out making it what would seem to be two separate radiator circuits in our house. They feed each of the two 1.25" PEX lines right into separate 2.5" lines which go on to step down and feed the radiators. There are, of course, two 1.25" PEX returns to the furnace to match these feeds. The cast iron original feed lines in the house run a loop and the radiators come off of them in separate feed and return lines, so valving off and one or more radiators in the house doesn't stop the flow downstream to others.
So, long and short of it, is that we'd appear to have two 1.25" PEX feeds going into what would seem to be two separate loops in the house radiator-wise, each with their own 1.25" PEX return to the furnace. I'm quite certain now that these two separate loops do cross over somewhere in the plumbing under the house since it is possible to push water into one feed at the furnace (using a garden hose) and, ultimately, get water out of both return line boiler drains. Whether this potential crossover inside is a problem or not, I don't know.
ANYWAY... for over a week now we've been running it and it is heating the house pretty well. No real complaints there. Here is our problem:
We keep losing water. I've had someone go through all of the crawl spaces under the house and they found absolutely NO leaks in the radiator plumbing. No damp spots. No water. No weeping. Just old, heavy, solid pipes with fittings you'd probably never get apart. This part of the system seems to be intact.
We had some leaks in the feed valves of the old radiators at first (they were ancient), but all of the leakers have since been replaced with new brass radiator valves and they seem fine. The old ones that didn't leak seem to still be intact. We've seen NO signs of water in the house on any part of a radiator after those replacements went in. Not on the floors, at the connections, etc. They, too, seem intact.
But the Heatmor bladder keeps going flat a day or so after topping it off and I can begin to hear gurgles in the radiators when the pumps stop or start. When the system is first topped off and the bladder is at a proper volume, anytime the pumps stop (thermostat satisfied or switched off manually) water comes out the pipe on the roof of the furnace. This will happen repeatedly as the pumps stop throughout the next 12 or more hours until, I suppose, enough water has come out that this doesn't happen anymore. By this point, though, the bladder stays flat all the time and I'm quite sure we've got less than proper water leading to possible boil-offs, overtemps, etc.
If the pumps are running, I can bleed all the radiators and, after a top-off of the Heatmor, get very little air out and almost immediate water from the bleeder valves. I discovered the other night that if I open those bleeders with the pumps off, the hissing I am hearing (which will go a LONG time) appears to be water being sucked into the radiator rather than bled out. So, obviously, I've stopped doing that. I now only bleed them (mostly to test the system) when the pumps are running at the furnace.
We had one radiator whose valve hadn't been replaced at first and it hissed all the time. In retrospect the other day, I realized it might have been sucking air in as much as anything. It has since been replaced and is now quiet. That radiator, too, has no bleeder on it due to a cramped space (no room for the valve). Even now with a new feed valve on it, I can hear it making trickling/tinkling noises inside faintly. I suspect it has a great deal of air - even though it heats up pretty well - that has never been bled off. I am tempted to shut that radiator off entirely or even remove it and cap off the feed and return pipes (as we've done with one other in the house).
So, in summary, no matter what I do, we seem to keep losing water and I suspect it's all coming out the top of the Heatmor rather than from a leak somewhere. The suggestion from the dealer right now is that we have an air leak somewhere (?) that is allowing pressure to keep building and blowing the water out of the furnace. If we do, I've not found it. I also have a hard time imaging we have an air leak if water wouldn't come out in a visible way when the pumps are on or even off. Thus far, we've found NO leaks of water... so how would we get leaks of air? Maybe a leaky bleeder valve that isn't losing water? If so, would I not hear that air sucking in with close inspection?
This is getting pretty frustrating, so I'm hoping someone with a wood furnace and old cast iron radiators might share their experience and point out something we might be doing wrong. If anyone else has ideas on how to test our system or changes we can make (hopefully minimal) to get this thing running right, we'd be forever grateful.
Sorry for the overly long post, but there is a lot to the story. I can answer any questions anyone might have, too, if I've overlooked a detail here that is useful.
Thanks!
- Aaron
Sweet Briar, Va
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Topic: New Heatmor: Radiator Pressure(?) Issues - Losing Water :( (Read 13030 times)