Zone valves or circulators in replacement boiler install

[shoottmx]

We've recently retired to our long term retirement home and are getting all the systems in tip top shape so we don't have to deal with them years down the road. We are having the existing 27 year old oil fired BB hot water boiler, controls and valving replaced with a Viessman propane boiler with everything new except the piping. We have 4 existing heat zones plus an indirect HW heater for a total of 5 zones. My shop is in the basement so we will make provisions to add a 6th zone for heat if necessary. Thinking the smaller more efficient boiler won't provide as much "unintended" heat to the basement as the old system.

The current system has a separate circulator for each zone which makes complete sense to me. If one zone--read circulator--fails, all the other zones have heat. Two different reputable local companies are recommending a single variable speed circulator and zone valves which they say is quieter, more trouble free and takes less power to operate than multiple circulators.

Wondering what the WN braintrust thinks??

Thanks for your thoughts,  g

[barnowl]

http://www.taco-hvac.com/uploads/FileLib...00-1.8.pdf

[jteneyck]

There would be more money in it for those companies to sell you a circulator for every zone, so if they are not it's for good reason.  I'd go with their recommendation.  If you are really worried about the circulator failing have it plumbed and wired for easy removal and have a spare on hand.  

I have a two zone system with a single pump.  I've replaced the pump once in 35 years.  

John

[blackhat]

There are some significant advantages to the system they recommend in terms of control setup and wiring. There may be a slight savings in electrical consumption as well. There should be no noise with either setup except perhaps an older pump with a rattle. I would probably design and recommend something close to what you are being offered.

[TDKPE]

Sounds like the single engine vs twin engine airplane conundrum.  With a single, if you lose the engine, you’re in an emergency situation, and have to land.  With the twin, if you lose one, you’re still in an emergency situation, though not necessarily coming down right now, but you normally have to land at a higher speed than the single.  

But with the twin, you’re twice as likely to be in an emergency situation in the first place.  


Personally, I’d stick with multiple pumps.  I’ve had bad luck with zone valves, and pumps are easy to replace.  Those tiny motors don’t use much energy, and all that energy goes into the space anyway in the form of heat, including the heat added to the water from the pump.  It’s electric heat, but a very small percentage of the total system heat.

[shoottmx]

Thanks guys--Good food for thought. Didn't realize there were cartridge replaceable circulators available. The cost difference for multiple circulators isn't significant to the total project --$434 additional for 5 zones. The power consumption isn't a worry either. We simply want a worry free system for the long haul.

We appreciate your responses.

g