I currently have 4 Zones in my house I want to add three more. Currently a series 100 Bell and Gossett pumps the water back to the Boiler. I am wanting to re-configure the piping in the boiler room. The new header will have three pumps pumping water from the header to the new individual zones and back to the return header.The four existing zones I want to continue using the four zone valves with one pump pumping water from the supply header to the zone or zones, depending on how many are calling for heat. I was told a lot of circulators are way over sized for what I am currently doing.

Question is do you do a head calculation for all four zones, then size a circulator for the total?
I read that you should do a head calculation for all zones, then take the zone with the largest head and size a circulator for that zone and it will be large enough for all four zones.

Any thoughts or opinions on this.

NJT you woke me up on pump curves sizing, Thanks

 

if doing zone valves or multiple loops on a given thermostat you size the pump for the highest head loss.
Why so many zones. Over zoning will cause the boiler to grossly short cycle and cause more maintenance issues. May cause you to add a buffer tank.
Buffer Tanks

 

Thanks for the reply, I had read that but wanted to see if any others thought along the same lines. The house currently has 4 zones, one of them is in floor, an in floor zone I put in back in the early eighty's. I no longer use it, but I might later on. I put an addition on the house a few years back so two of the new zones will be in-floor radiant heat with their own pump's supplying water. The other was a zone I never finished when I built the house. It goes to a unit heater in the garage. I do not have room in the boiler room for a buffer tank, so I would have to get creative to put one in there.

 

Keep in mind the more zones you add the boiler will short cycle more causing lower effciiency and more maintenance issues.

 

rbeck, Thanks for the suggestions, I do not know any other way to do it. The addition was a 14' X 18' two story rooms. The upstairs part being a four season porch and the room below will be used for storage. So that will be two very small zones. The garage is quite large so that might be another issue because I will not be heating it constantly. I will try to get a profession to look at what what I have. One person has told me he will come out but was a no-show.

 

Need to avoid any potential of freezing.

 

The room for storage and the garage probably don't require close temperature control so using thermostats with wide deadbands (four degrees or more minimum) will help to reduce short cycling.