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Stay with Apollo from '80's or go gas heat??


Ken12
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Moved into the 2 level 3,000 sq ft home in '93. One Apollo unit on each level, each with 50 gal Apollo water heater--circ 1986, probably when the house was changed out from radiant heat to hydro-heat system.

The system has worked well, but in recent years the upper unit has developed a vibration noise on the return end (probably the Grundfos up15-42su return pump) that is annoying. Also, there was that common problem of a small leak at the heat coil/intake pipe, but it actually stopped of its own accord years ago

Wayyyyyy overdue to replace the water heaters. No one, I mean no one wants to work on these units. Drop 10k on gas or 3k on two water heaters and new return pump???? Opinions appreciated

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From your response, I take it that they provide domestic water as well as space-heating water.

If so, then it makes the most sense to buy two new water heaters and keep the hydro-air system. Otherwise, you'll end up buying a new gas warm-air furnace AND two new water heaters.

For servicing, find a tech who's willing to learn the system and stick with him. These things aren't rocket science. They're easy enough to maintain & troubleshoot.

- Jim Katen, Oregon

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If that system has been in continuous use since the 80's without a plate exchanger to isolate the domestic use water from the AC water, you might have some pretty clogged up coils there. Talk to an automotive radiator repair shop about getting the coils acid dipped and flushed and then consider installilng a plate exchanger and an expansion tank and second circulator on the AC side.

ONE TEAM - ONE FIGHT!!!

Mike

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If that system has been in continuous use since the 80's without a plate exchanger to isolate the domestic use water from the AC water, you might have some pretty clogged up coils there. Talk to an automotive radiator repair shop about getting the coils acid dipped and flushed and then consider installilng a plate exchanger and an expansion tank and second circulator on the AC side.

Why would the coils be more clogged up than any other hot water pipe in the house?

It seems like the clogging would only occur if the coils had heat applied to them from the outside and the water inside was being heated. Then you'd get minearal build up just as you do in a water heater. But in this system, the hot water is circulated through the coils and *cooler* air is blown over them. Why would this cause clogging?

- Jim Katen, Oregon

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"Domestic water" as opposed to drinking water or?? Plate exchanger?? Sorry guys, I wondered into the 2 Apollo's 17 years ago fat, dumb and happy.

Changed out a filter yearly, have noticed a small leak in the bottom of the casing that stopped before I even had to deal with it and have had the return pump making noise when it kicks on for far too long.

That's all I know about the system. Appreciate the advice. Attached pics should give you some idea of the upper floor system that has been used the most in the past 17 years we've had it. Pic #1 is in kitchen. Pic #2 is on the opposite side of same wall in garage where the heat exchanger is installed.

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"Domestic water" as opposed to drinking water or?? Plate exchanger?? Sorry guys, I wondered into the 2 Apollo's 17 years ago fat, dumb and happy.

By domestic water, I mean water that comes out of the taps. Since your water heaters provide water for sinks, showers, & tubs, you'll need new ones when these go anyway. So it makes sense to stick with the hydro-air system instead of replacing the water heaters AND installing new furnaces.

By plate exchanger, Mike is talking about a system where the water for heating never touches the water for other things.

- Jim Katen, Oregon

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Hi Jim,

Aren't the Hydro Air coils almost the same configuration as a car radiator; thin tubes surrounded by thin fins?

It's the thin tubes becoming clogged with lime deposits and other gunk that impedes circulation that I'm thinking about. That's why I suggested acid cleaning.

There's a lot less wear and tear on these systems with a plate exchanger and if you get a leak in the water heater or vice versa you don't have to worry about completely depleting the other system.

ONE TEAM - ONE FIGHT!!!

Mike

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Hi Jim,

Aren't the Hydro Air coils almost the same configuration as a car radiator; thin tubes surrounded by thin fins?

It's the thin tubes becoming clogged with lime deposits and other gunk that impedes circulation that I'm thinking about. That's why I suggested acid cleaning.

There's a lot less wear and tear on these systems with a plate exchanger and if you get a leak in the water heater or vice versa you don't have to worry about completely depleting the other system.

They're similar to car radiators, but not so thin. I think that they're made from 1/4" tubing or something close to that. I've just never heard of gunk accumulating on copper tubing that had fresh water running through it.

- Jim Katen, Oregon

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I've just never heard of gunk accumulating on copper tubing that had fresh water running through it.

I've seen or replaced dozens of clogged domestic coils in boilers.

Yes, as I said in a previous post, if heat is applied to the tubing from the outside, it'll cause mineral build-up on the inside of the coil. But in a hydro-air coil, you aren't applying head to the coil, you're blowing cool air over it.

I don't see why the coils in a hydro-air system would clog up anymore than any other copper hot water pipe.

Just running hot water through a pipe doesn't cause it to clog.

- Jim Katen, Oregon

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I've just never heard of gunk accumulating on copper tubing that had fresh water running through it.

I've seen or replaced dozens of clogged domestic coils in boilers.

Yes, as I said in a previous post, if heat is applied to the tubing from the outside, it'll cause mineral build-up on the inside of the coil. But in a hydro-air coil, you aren't applying head to the coil, you're blowing cool air over it.

I don't see why the coils in a hydro-air system would clog up anymore than any other copper hot water pipe.

Just running hot water through a pipe doesn't cause it to clog.

- Jim Katen, Oregon

Hi,

Yes, I see your point; but I still wouldn't discount the possibility that a 30-year old coil could become clogged with crud if it's been circulating ordinary domestic water instead of boiler solution for that long. He says he had a leak but it stopped of its own accord? Hmmm?

The domestic hot water circuits on a house are subject to more scrubbing than a hydro coil with narrow tubes because they are in constant use but these systems aren't supposed to have water continuously run through them because scrubbing can cause problems; at least that's what I seem to remember someone teaching me about hydronic systems someplace.

Don't these things basically sit with water in them outside of the primary flowstream for months on end? Yuck! Hope they've got a timer and circulator on that system that cycles the system once a day regardless of season.

I've just always thought of these things as the equivalent of car radiators. Like a Hydro Air coil, car radiators have a pressure-relief device built into the system and they have a lot of cold air passing through them but they crud up anyway. Sometimes even car heaters get crudded up; that's one of the reasons (At least I think it is one of the reasons) that they began recommending very high concentrations of specialized coolants in those systems decades ago.

If one had a Hydro-Air system with a plate exchanger running something like propylene glycol instead of water, wouldn't the coils stay cleaner and be less likely to clog up?

Back to the OP and another possibility; I wonder if he's had the system opened up and actually been able to see whether that coil is clean on the outside or whether there is 3 decades worth of dirt and crud preventing airflow through it?

ONE TEAM - ONE FIGHT!!!

Mike

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" Plate exchanger?? Sorry guys, I wondered into the 2 Apollo's 17 years ago fat, dumb and happy.

Hi,

Well, this isn't a Hydro-Aire system but it does a pretty good job of illustrating what I mean. The shiny rectangular object at the center of the photo that's highlighted by the elipse is a plate exchanger. If you look closely, you can see that there are two circulators; one for domestic hot water and the other for the in-floor heat. There is a tempering valve on the domestic hot water side so that the hot water circulating to the hydronic system can run hotter. The expansion tank is on the closed hydronic heating loop.

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ONE TEAM - ONE FIGHT!!!

Mike

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