Best solution for heating CI rads

[binfordw]

Recently finished my outdoor wood gasser, and am looking for better solutions to heating the house.

I have CI rads in the house, which I currently plumbed up directly to the pex lines from boiler. I have a bypass line with a solenoid valve, and a solenoid on the hot feed, past the bypass ofc. House thermostat shuts bypass+opens feed, or vice versa.

This works, but Im noticing the stove idles long periods, and the house goes long periods between calling for heat, due to the rads holding heat so long. When they do cool enough, that cool water is sent all at once to boiler, dropping temp 20-25 degrees or more nearly at once.

I feel there should be a better way. I'm thinking about using a mixing valve to lower the temp to the rads, as they really dont need 160+ degrees to heat the house after all. Are there better solutions to this?

 

[tom in maine]

There would be several ways to do this. The simplest might be an injection loop that is controlled with an outdoor reset control.
This would modulate the water temperature to the radiators based on the outdoor temperature.
Each radiator could or should have a thermostatic control valve to protect the room from overheating ( in case of a sunny day or other
uncontrollable heat input to the space.)

Radiators were originally designed to work with solid fuels (wood or more likely coal). They delivered constant heat. In that situation, the
the firing of the boiler controlled the heat output. The manual valve on the radiator worked to control the overheat a long time ago when the valves were new.
Most do not work very well after 50+ years and are prime for replacement with a thermostatic control.

 

[salecker]

Hi
I'm using CI rads to heat our house.
I have a wood boiler hooked to storage,and a backup oil boiler.So far i have two zones hooked up and are working great,very impressed by the CI rads,first time living with them.
I went with TRV's on each zone.They are supplied from a manifold in my basement,which is supplied by underground lines that have a circ pump running continuously.For the house manifold i used an Alpha pump.I will be hooking up4 more zones on the main floor of the house.
The TRV's are the ticket to comfortable heat in your house,they are set to maintain constant room temp.
If you were to use TRV's i think you would get away from the large blasts of cold water headed to your boiler.There is always some movement through the rads unless it's too warm outside to require heat.
TRV's work without power so in a outage you will still get some heat by thermosyphon.
Thomas

 

[binfordw]

Hi
I'm using CI rads to heat our house.
I have a wood boiler hooked to storage,and a backup oil boiler.So far i have two zones hooked up and are working great,very impressed by the CI rads,first time living with them.
I went with TRV's on each zone.They are supplied from a manifold in my basement,which is supplied by underground lines that have a circ pump running continuously.For the house manifold i used an Alpha pump.I will be hooking up4 more zones on the main floor of the house.
The TRV's are the ticket to comfortable heat in your house,they are set to maintain constant room temp.
If you were to use TRV's i think you would get away from the large blasts of cold water headed to your boiler.There is always some movement through the rads unless it's too warm outside to require heat.
TRV's work without power so in a outage you will still get some heat by thermosyphon.
Thomas

The TRV's sound interesting, I need to look closer at how my rad's are plumbed in. I just removed the existing fuel oil furnace, and tied into the pipes with feed from my boiler. If its a main line, with all rad's t'd into it, they should work, as I'd still be circulating even if all rad's TRV's are closed off.

Did you use remote Tstat TRV's?

Thanks for the info guys, It sounds like TRV's are something I need to look at closely.

 

[salecker]

Hi Binfordw
I went for the TRV's that are right on the rads.They aren't pretty,but my plan is to place a piece of scrap rock on the tops of the rads.That will distract from the TRV's as they will be under the rock.
Thomas

 

[Jeff S]

Currently sending 110* to my Rads using injection feed like Tom is suggesting, very simple to do in fact sounds like you already have some of the parts(solenoid valve) all though after the bypass is not where I would have installed it but before. Also would need some kind of aquastat to control your temps. I've had my storage tanks as high as 200* and send only 110* to my rads ,during last years bitter winter a simple adjustment and I was able to bump that up to 130*.

One big advantage to using the lower temps beside the even heat is that stand by losses are minimized (you keep your BTU's in you insulated storage until needed)

 

[Jeff S]

I went back and read your post to get a better understanding, sounds like you have 1 circulator and 2 solenoid valves with one valve always on and the other always off depending on the thermostat to make the switch . With this scenario either 100% is feeding back to boiler or 100% is feeding your load in which case you will get cold slugs returning back to boiler which will cause you flue gas problems harming your boiler.

If you have this set up as I think you have you have, here some simple options to help with mixing all of which could be controlled with 1 aquastat measuring your return boiler temps.

1 - Install an aquastat the reads the temps returning to boiler and only allow your bypass solenoid to close when return temps are over 140*.

2 - Either eliminate bypass solenoid or energize it so its always open then using the aquastat to control your feed solenoid allowing it to activate(open) only when return temps are 140*.

3 - Let both solenoids function at there present state but only activating when return temps are over 140*

I like option 2 best , none of these scenarios provide you with lower temps to the rads but will help you protect your boiler at the minimum cost of a aquastat .

To lower your temps to rads I still like the injection feed but would require at least 1 aquastat and another circulator which of coarse would require you to shut down your system and do some more plumbing.

TRV's would be nice but you would need to install on all Rads.