I currently have a 2 zone FHW system. The boiler is a Weil-McLain Gold CGA5 with 2 circulator pumps and no zone valves. We have one room that is part of an addition that is a few degrees colder than the rest of the rooms on the first floor. For maximum comfort, I would like to make it a separate zone.

One plumber plans to add another circulator pump to the system. The other plumber plans to use zone valves. My existing switching relay (Taco SR506) has more than enough room to support another pump. Still, I'm leaning towards using zone valves. The reason is that I will probably make the first floor into 3 zones. The original piping for the first floor looks something like the number "8". The boiler sends water out and it splits into 2 separate loops before returning back to the boiler. Two owners ago, they added a first floor addition by "extending" one of the loops.

This room is a little colder than the rest of the house for a number of reasons: 1. It's the last part of the loop so the water is a little cooler. 2. It's above an unheated basement. 3. It's on the north side of the house. 4. There's a massive masonry fireplace that acts like a cold sink.

I'm working on better insulation for this room but will make this a separate zone this summer.

I have some questions about using zone valves that you might be able to answer:

1. On Bell & Gossett's website, they seem to imply that zone valves is old technology that modern systems tend to use small circulator pumps on each zone. I guess in the older days, systems were designed with a single large pump and multiple zone valves. Do people still design systems using zone valves or should one stay away from them? My friend said that he would have to replace the power head on his zone valves from time to time because they would go bad. I don't see much difference between a zone valve going bad versus a circulator pump. Well, you can replace a zone valve head without having to drain the boiler. This past winter, my Taco (less than 2 years old) went kaput and my plumber had to replace it.

2. Looking at the Taco product line, I have the option of using a zone ball valve or the 560/570 valve. Why would I choose one over the other? It seems that the zone ball valve is the better technology but more expensive.

3. Do zone valves make a lot of noise (e.g, water hammer?) or are most models reasonably quiet?

4. What is the typical life expectancy for a zone valve as compared to a circulator pump?

Thanks,
--Bill

you can replace a circulator without draining the boiler if you have isolation flanges on either side of it.
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anyone who installs a circulator without putting these on is doing their customer a diservice.
circulators now can be bought with a flow check built in so no need for a seperate flow check.
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i see more problems with power heads for zone valves than i see with 007 circulators.
the installation would be cheaper if you added 2 zone valves since you would not need to relocate the existing circulator. nor would you have to buy another circulator.
if you go with zone valves, make sure they put seperate pugre set-ups of each zone. while they have the piping apart, change the circulator flanges to isolation flanges.

If you put more then three zone valves you will most likely need to add another transformer.

Also if your circulator fails during the night, you wont have any heat throughout. With seperate circulators, you will be able to have heat until the circulator is replaced.

In my opinion using seperate circulators is a better job.

Chris

Packy, thanks for the info.

In your experience, what's the typical life expectancy of a 007 pump? The one that was replaced on my system a couple of months ago was just shy of 2 years. The plumber replaced it with a Grundfos. He said that the Taco pumps have a 1 year warranty but usually last 10 years or more.

The Taco pumps have a replaceable cartridge. I asked him if there was any advantage to using them. He said not really because in order to replace the cartridge, you still have to drain some water from the boiler. Is this true?

i believe the taco cartridge has a 5 year warranty.
with isolation flanges on either side of the circulator, you only lose about a cup of water when replacing the cartridge.
there is no set lifetime for either grundfos or taco. they are both fine pieces of equipment and i wouldn't hesitate to use either. i use taco because that is what the local supply house carries.
as far as your changing to 2 zones, installing 2 zone valves would be the easier way. the wiring would be more difficult.