Hot water heating zones, pros and cons

[MoneyPitGuy]

I'm rehabbing a 3-story 1911 house outside Philly. I have a new boiler. I'm pretty sure I want to zone the system. It's just the wife and myself, so there are several spaces that don't need to be fully heated every day. I have a couple of questions as I research the topic. 1) Should I be concerned about short cycles? The boiler seems a good fit for this house. If I could achieve a 30 percent drop in run time am I raising a risk of short cycle problems? 2) Which is better, valves at the boiler or valves at the radiators? I've seen TRVs and some thermostat controlled valves and it seems like valves at the radiators is ultimately simpler. On the other hand it seems like you could set up valves at the boiler so you could do repair and maintenance without draining the entire system. Any thoughts, suggestions, or resources for further research? Also 3) what about cost recovery? How long is it likely to take to recoup my money? Thanks.

 

[hj]

ANY valve at the "radiator" means that it must have its own supply of water, either from a main or the boiler. Valves at the boiler are normally only "service valves" NOT for room temperature control. Valves at the boiler and valves at the radiators are two completely different items. Are you sure you want to DIY this project? Do it wrong, (and it will be very easy to do it "wrong"), and you will NEVER be satisfied with the system's performance. Depending on what you are comparing it to, you may NEVER recoup your money.

 

[Sponsor]

 

[Tom Sawyer]

It all depends on how the current system is piped. Many times the cost of zoning far exceeds its savings.

 

[DougB]

Traditionally, how it's done is that you have a supply and return circuit for each zone. Each zone has a circulator pump. The low voltage thermostats are connected to relays - these relays are 'or-ed' together - so if one zone calls for heat - the boiler will ignite and the realy turns on the circulator for that zone.

To me - having a valve at the radiator / baseboard would be a maintenance problem. I haven't done HVAC work in 30 years, but the 'little' TACO valves were a PITA. Having to service them in a finished area - no thanks.

You would have to add / repipe your building.