Any HVAC folks here?

[Siress]

We have two of these cooling/heat pump convertible air handlers that are only being used for AC: Trane Model# 4TEC3F36B1000AA. We have an entirely separate system for heating; natural gas boiler with baseboards. The heating system is at 2x it's end-of-life. It is plumbed for 4 zones via solenoids sharing 1 circulation pump serving all ~3k sq-ft, and that pump just went out - or at least stopped pumping at full flow rate. I couldn't tell anything doing a sound check since the blower motor is 2' away, and I haven't hooked up an ampmeter yet to see what the current draw is exactly. The pump is in real rough shape, though. Motor housing corroded from a seeping leak at the top gasket and a 4" long crack right on top of the housing.... it's comically bad. Looks like I could probably pry the housing off with a screw driver. For that reason, I already procured parts to replace the pump so I'll get us through the holidays. Longer term, though, we'd like to add a gas furnace to our existing air handler if possible. I had a local company quote the work at >$20k for both air handlers; one in the basement and another in the attic. They then quoted some other work that I am competent at for ~3-4x what I'd expect, so now I'm curious if someone in the know can help me out. What would it really take to add natural gas heating to these air handlers? The house has a 200A line to it, which might be enough to use electric heating instead - but I think that'd cost us a lot more in the long run as we pay a lot for electricity in this area.

So... Does $23k sound reasonable for adding natural gas furnaces to two of these air handlers? The short-hand for their quote was:
1) INSTALL GAS LINE FROM MAIN 1" LINE TO NEW BASEMENT FURNACE LOCATION AND EXTEND TO NEW ATTIC FURNACE ALONG EXTERIOR WALL.
Why not reroute an existing baseboard waterline up to the 2nd floor and connect it to a heat exchanger in the air handler instead of adding a exterior gas pipe and a second furnace in the attic?
2) INSTALL AN 80% AFUE FURNACE IN ATTIC. VENT THROUGH ROOF. INSTALL AN AC COIL AND REATTACH REFRIGERANT LINES. INSTALL A MEDIA FILTER. NEW ECOBEE THERMOSTAT AND UPDATE THERMOSTAT WIRES.
What's this about an AC coil and media filter? Existing thermostat wire has 6 pairs.... pretty sure it's good for whatever. They didn't take the thermostats off the wall to check. And why lower efficiency for the attic, anyway?
3) INSTALL A 95% AFUE FURNACE IN BASEMENT, VENT THROUGH SIDEWALL. INSTALL AN AC COIL AND REATTACH REFRIGERANT LINES. INSTALL A MEDIA FILTER. NEW ECOBEE THERMOSTAT

[Mr. Hick]

It's christmas eve, I'm kinda drunk and maybe I'm confused.

You have a forced hot water heat via hydronic baseboard? why would you install two boilers to convert the home to forced hot air? -- Am I misreading that? As far as your circulator pump being dead: Probably. If you can get the numbers off of it you can find one at the local F.W. Webb and youtube that with basic tools.

Forced hot air is way and below hydronic baseboard heat. loud, terrible exchange rates and less desirable, nose bleed inducing, dust spreading heat.

Are you just trying to "Consolidate" your units and use your already existing handlers? are you going to tear out your baseboard?

as for $23k for the cost of installing two heating units... I would say that's average. the whole housing boom has made anything required to be installed by a licensed professional to practically double in price in the last 3 years.

[Siress]

Well. Crap. Thanks for the eval.

The only reason to convert is that my wife hates the baseboard heaters, and this system needs overhaul regardless. Personally, I love the hot water baseboard heating for all of the performance reasons you mentioned. I'd like to remove the solenoids and add a pump for each zone, though. Not big on single points of failure like this.

[Mr. Hick]

Absolutely. That's an outdated(but far cheaper) way to handle it. I would get a pump for each zone (watch your required amp load though, noids don't draw as much as pumps) and add a temperature gauge on the working side of the line so you can identify any further problems and isolate zones immediately.

I would really, really try to convince your Mrs. to keep the baseboard. You can buy new wall brackets or even install new radiators if it makes her happy. it's a far superior and far more efficient way to heat the home.

Hell, it would be better to convince her to spend the money switching over to floor radiant on the first floor (I'm assuming you have a cellar like the rest of us new englanders)

[Siress]

That's a good call on radiant floor heating. I hadn't considered that, but we do have a completely unfinished basement at the moment - and I'd already like to get at the joists to resolve some creaks and squeaks. If we do end up replacing the boiler, what do you recommend? We currently have a gas water heater that's also beyond end of life, but probably good for another decade. Still, I think it'd be efficient to get a boiler with a spare zone we can use later for supplying hot water. Thoughts?

[Mr. Hick]

I'm not installing boilers everyday, but all the plumbers I trust in my area are installing Viessmann boilers. Between modulation, good user interface and readily supply of non-Chinese made parts they are a big hit. You could install a "combi" system that also runs hot water continuously or have a zone set aside for a tank style water heater. there are good and bad for both styles. If you don't mind doing the leg work on running lines and plates you would be better suited to do most of the work yourself next spring and have a plumber install the boiler, exhaust, and live manifold next summer when they are less angry and busy compared to winter.

I would definitely take a hard look at what you have already too. A new unit will likely require some re-wiring and draw a completely different amp load then your old one. Not to mention the live side manifold may end up needing to be completely replaced depending on how much of the heating system you re-work.

[Siress]

Thank you for the tips!

Part of the replacement will be relocation to get it next to the HVAC system, so the manifold is toast anyway. What is a "plate" in this context? I'm confident I can do the work given a plan - except for the gas line stuff - but I don't trust myself to have the best plan of action here. I was in fact looking at the Buderus combi unit, but I'll change my sights to Viessmann.

[Mr. Hick]

"plates" are literately metal plates that screw into the subfloor, then the PEX clips into the plates, its to transfer the heat from the radiant floor system over a larger area of the subfloor. don't skip them.

[Siress]

Ah, cool. Makes sense now. I've only ever looked into radiant floor heating for bathrooms, which have what looks to be plastic trays that the PEX goes into before getting tiled over. Makes sense that this application needs more of a heat spreader. Thanks for all of your help and info!

[Mr. Hick]

"I've only ever looked into radiant floor heating for bathrooms, which have what looks to be plastic trays that the PEX goes into before getting tiled over. Makes sense that this application needs more of a heat spreader. Thanks for all of your help and info!"

While completely possible, try not to run radiant above wood subfloor. If there is ever an issue where a line fails, or the floor flexes and rubs a hole in a line you DO NOT want your heating system to be stuck between tile floors and the subfloor. I did an insurance job about 6 years ago because a weeping radiant line compromised and leaked slowly, causing absolutely stupid amount of money to fix. if it had just been under the subfloor the issue wouldn't have happened, and if it did would have been caught significantly quicker.

[flyweightnate]

Minor point... if the Trane systems can run as heat pumps, what needs to be done to make it happen? They're pretty useful in the shoulder seasons and are a decent backup if the gas goes out.

Current regulations are also dramatically increasing the price of gas. Some people suggest 50% this winter alone; methane capture regulations might double it in the near future. Getting a quote on running those as heat pumps might be the cheaper solution; gas may be years to pay back.

But yeah... boilers are extremely hard to beat for efficiency.

[Siress]

That's a good question, flyweightnate. I'm not sure. Any idea, @Mr. Hick?

I just finished swapping out the circulation pump a moment ago. All is running well. It was working surprisingly well off of gravity feed only. Check out the state of the pump I removed... I'm now thinking this entire house has been just gravity feeding for a long time.

I didn't have the parts to replace the flanges like I wanted to - and add a shut-off valve between it an the boiler - so I had to resurface the existing flanges and hope for the best. Seems to have worked a treat.

[Mr. Hick]

Dude: that's amazing that the thing was even running! if the pump is that sour I'm guessing that you would be better suited to start debating how to re-work that system. as for the Trane systems, if you can go out and find the product number and serial on the information plate on the pump system outside you can identify if it's capable as a heat pump (or can be converted) or if it's just a refrigeration unit.

Also: as long as your system isn't leaking and water is circulating I wont worry about it too horribly much. if you notice a TON of water hammer in your baseboards (bang, bang, bang!) you need to purge the air from the system. Hopefully that isn't the case.

[Siress]

Sadly there wasn't a way to shut off water from the system. The only valves within the closed loop at all were the zone control valves... so pretty much the entire system drained just so I could pull the pump off. Took quite a while to bleed since there wasn't a drain or outside access within reach of a hose. I was carting buckets about 80yrds away. Probably best not to dump all of the sediment and junk into the septic anyway. The bleed water was black...black as night. Probably conductive and magnetic; ferrofluid. Had it running somewhat clear by the time all of the air was out. The last boiler I had didn't have a functioning air bleed because it was installed without a vertical columnto collect air. ಠ_ಠ I was pleased to find that this one works well for getting out the remaining little bubbles. It's silent now, so I'm not even going to bother checking the baseboards.

With the old pump, we had a ~8deg differential between bedrooms on a single zone, and now there is a 2deg differential. I'm seriously doubting that old pump was working since we first moved into the house. What's frustating is that the aquastat was replaced a year or so ago and they hooked it up to this pump.... there's no way that much corrosion happened due to a seeping leak in that amount of time.

Re: Condensers, "Silver Series SI" model 4A7M3024A1000AA mfr 7-2010. I haven't found a manual or spec. sheet for it yet.

edit: I just noticed that the air handler has a honeywell "equipment interface module" installed. I looked up what that is and it sounds like it's for zone control...which is fascinating since we were told there's just one zone per air handler. Perhaps it's just for the humidifier...