Best setup for house heating - zone valves or circulator pumps?
June 17, 2017 7:17 AM   Subscribe

Our house is from the 1950s and the heating system has been hacked together over the years, so we're looking to redo the whole thing for max efficiency. I've received two offers: one to replace the zone valves, and one to install circulator pumps. Which is the better solution?

There are three different types of zone valves around the house right now: some original, the rest newer. None of them are connected to the boiler, so the house heats as one zone. On top of that, some of the zone valves are getting stuck open, causing parts of the house to be super hot.

So we're looking to redo the system this year. Everyone has said that the best thing to do is to basically use what's there as best we can, and do a once-over replacement of everything to bring it up to latest practices for max efficiency. We've decided to split the house into six zones, and the house is a fairly long. I've got two offers from vendors right now: one to replace the zone valves, and one to install circulator pumps.

From what I've read, one is not necessarily better than the other. Some people say modern zone valves are better than they were, and other say they still fail. On the other hand, having each zone have its own circulator pump means that if one breaks, the others still work. But with each pump having its own circuit, does that mean more water would need to be heated for the whole house? And maybe at some point down the line we'd replace our super old boiler with something more efficient.

Clearly I have no idea what I'm doing, I thought I'd query the hive mind. Any ideas/opinions?
posted by gchucky to Home & Garden (2 answers total)
 
One thing to think about is electricity usage. Our (old) circulator pumps use a ton of electricity. An advantage of zoning with different circulator pumps is that you'll only turn on the pumps you need. Zoning with zone valves means the (one, big) circulator pump has to be on if even one zone needs heating. Modern, multi-speed circulator pumps may make this not a huge difference, but it's worth asking about.
posted by Betelgeuse at 7:27 AM on June 17, 2017


Just replace all the valves all at once, and treat the whole house as a zone. Then you have one thermostat, and one temperature throughout, with cold spots or warm spots depending on insulation or solar orientation. Make sure they flush the whole system, and make sure you haven't rusted. If there is some electrical screw up, and the system picks up an electric charge, the boiler can rust out. It should be a closed system, with just a couple of gallons of the same water recycling. So if they drain the system, make sure they use distilled water, after they flush it with regular water. They should have a charging pump for this.

If one pump breaks, it might freeze and you have no circulation through the rest of the system. I had a water baseboard system that we installed. The pump went along for nearly 20 years with no problems until it croaked just after Christmas one year. I didn't realize at the time, the fill valve had sprung a leak and was leaking cold water into the system. The people the ultimately bought the house did away with the whole thing.

One pump worked just fine for 20 years, and $88 dollars later it was working again. Simple makes things easier to diagnose. I fixed this for about $109. The lowest off I got to fix it was $1,100. Simple leaves you less at the mercy of "experts."
posted by Oyéah at 11:53 AM on June 17, 2017


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