Hydrostat 3250 Plus Question

FMA12479

I have two heating zones that are Forced Hot air by Hydro (air handler) and an indirect Water Heater storage tank. Will a Hydrostat 3250 with outside sensor upgrade worth it? How should it be set up with the Indirect Hot Water storage Tank during the non winter months?

GGross

Personally I don't think you should replace with the 3250 for the reason of saving money. There is a priority circuit to connect an end switch for an indirect water heater on them, that would override your outdoor reset. they are nice little controls though

Steamhead

With only two zones, the OD sensor may not help much. But by all means upgrade to the 3250+. Add the ElectroWell and you have a low-water cutoff as well.

Robert O'Brien

FMA12479 said:

I have two heating zones that are Forced Hot air by Hydro (air handler) and an indirect Water Heater storage tank. Will a Hydrostat 3250 with outside sensor upgrade worth it? How should it be set up with the Indirect Hot Water storage Tank during the non winter months?

Depending on how the fan is controlled , you may not get good results. Hydrostat uses a temperature/time step logic. If your fan runs on a call for heat, no problem. If you have a temperature control on fan, you may get fan cycling and poor performance

EdTheHeaterMan

I have fan coils to heat my home in south NJ. I don't believe you are going to benefit from outdoor reset. Just my opinion. You would get the same temperature air from an inverter heat pump at a lower cost. (I'm not suggesting that you replace or install a new air conditioner in lieu of a control upgrade. It is just for comparison) The problems with fan speed and reduced water temperature in the higher outdoor temperature operation is not something that the control can be easily programmed for. The concept makes sense however the application is not easily implemented with currently available, affordable products.

STEVEusaPA

You'll never benefit from ODR with oil, without a buffer tank. And specifically as @Robert O'Brien mentioned, not good for hydro air.
However, the 3250 is a better aquastat. You can enable circulator hold off, and with a well change to their well, you get low water cut-off.

mattyc

I just finished an install with a 3250 plus with outdoor reset. There were two zones (baseboard) and 1 Indirect tank. If you read the instructions that come with the outdoor reset kit, it will tell you how to wire the indirect tank so that it bypasses the outdoor reset and goes to hi-fire. Off the top of my head I believe you pigtail a wire from ZR on the hydrostat to the 120v terminal where your indirect circulator gets power from on your switching relay panel but please double check that info and read the manual lol. if you wire through a switching relay panel and you adjust the high/low limit on the hydrostat correctly, (maybe 180high 140 low) then the reset curve shouldn't be too bad on the low end but you may have to tinker with that a bit.

FMA12479

Thank you all for the comments - My fan only comes on when it calls for heat - it looks like the big benefits of using lower temp to heat my house during the winter would only be if i had baseboard heat not soo good with Forced Air. BUT I will get a better Aquastat than i had before - thank you!!

mattmia2

Outdoor reset on forced air could work well if you slow the fan down to match the lower water temp but most residential air handlers aren't designed to do that(some AC and heat pump air handlers have the blower motor controlled with a modulating outdoor unit but the control is proprietary so a hot water outdoor reset control or temp sensor couldn't control it without some custom electronics)