The age old question: zone valves vs circulator pumps

jfromct

Hi all,

We decided on a boiler and an installer. The contractor has recommended that we replace our 4 zone valves with circulator pumps. I am somewhat against this as I feel that the zone valves are more energy efficient. I can certainly see the benefit of the circulators but fear that my electric bill will be $30 or so higher during the winter months. $30 isn't going to make or break me but doesn't it defeat the purpose of upgrading to a more efficient boiler? Connecticut has one of the highest electric rates in the country at something like $0.23 per KW. Am I over reacting? Would 3 additional pumps use much more energy than zone valves?

As always, your help is appreciated.

John

EBEBRATT-Ed

The price of a zone valve versus a pump are about the same. Yes pumps could use a little more electricity, I doubt you would notice the difference. Why not ask him?

Bottom if you trust your contractor have him explain it to you

SuperTech

Using the new ECM circulators will help reduce the power consumption.  One advantage is that circulators tend to be much more reliable than the Honeywell zone valves that I see used everywhere. 

Jamie Hall

Good arguments can -- or could -- be made either way, particularly with the older pumps which did use a fair amount of electricity. As @SuperTech tech said, the new ECM pumps use remarkably little (he's right -- you won't notice it) and have the advantage that they can be tuned individually to each zone.

EzzyT

I would look at it as if using pumps only would I be over pumping the majority of the heating season. That will have an effect on electrical usage but the most important is the effect it has on the overall system efficiency and comfortability to the end user.
What kind of hot water system do you have in your home @jfromct?

Big Ed_4

What type of heating zones are in the house ? Baseboard , Monoflow , radiators ? Baseboards what are the lengths of run

hot_rod

Ford or Chevy?
There are very reliable zone valves available if that is the determining factor I could suggest a brand:)
Is it possible zone valves will outlast computer driven circulators as far as the electronics reliability?

Delta P type electronic circulators, may be the best way to dial in the flow rate required by individual zones. The circ will recognize the changing flow requirements and adjust to that condition.

A flow setter would be needed to accurately dial in zone circulators, unless you trust the gpm readouts. May want to confirm those readouts.

If you install fixed speed circulators, a pressure bypass valve should be installed and properly set. Although it is a parasitic device, it sheds away excessive pump head, same amount of electricity used.

While mainly used on larger hp circulators, this graph from a recent B&G webinar, show the importance of running in the middle of the curve.

jfromct

EzzyT said:

I would look at it as if using pumps only would I be over pumping the majority of the heating season. That will have an effect on electrical usage but the most important is the effect it has on the overall system efficiency and comfortability to the end user.
What kind of hot water system do you have in your home @jfromct?

Funny you should ask. We installed a heat pump water heater at the beginning of the summer when the original boiler (coil) was showing signs that it was done. The idea now is to run the coil on the new boiler into the water heater. This should it allow the heat pump to keep up more efficiently in the winter but I'll be able to shut down the boiler in the summer to conserve oil.

jfromct

Big Ed_4 said:

What type of heating zones are in the house ? Baseboard , Monoflow , radiators ? Baseboards what are the lengths of run

We have baseboards in the house. I believe the total run length is something like 130 ft. Does that make sense? I have the info but it's not in front of me at the moment.

hot_rod

So 130' of fin tube split into 4 zones? If it were split evenly about 32' of BB per zone. Possibly some shorter?
Really should not need a circ on each zone that size. I guess it comes down to installer preference.

Robert_25

The contractor may have a good reason for suggesting multiple circulators - ask what it is. I would prefer zone valves, but that is based on my own experience.

A few years ago I replaced a couple circulators with zone valves and an ECM circulator that adjusts its output based on how many zone valves are open. It uses about 1/3rd as much energy, and we have noticed more even heating and less expansion noise in the baseboards. I think many systems are overpumped - mine certainly was.

GroundUp

Of course it depends on the system requirements, but in a case like yours with 130ft total BB element across 4 zones I'd be inclined to install a delta P ECM circ like a Grundfos Alpha2 and four Taco Sentry ball-type zone valves. There is almost no power usage, and almost nothing that could possibly go wrong with the valve body of a ball type unit like the Sentry. If the zones were larger, or had a high pressure drop, then zoning by circ makes more sense to me but an application like yours I really don't see the idea. Asking your installer why he wants to head that way would be the first order of business, and if you trust him there's no right or wrong answer here. There are hundreds of thousands of each type out there working just fine