cold oilburner circulator zone problem. Advice needed.

[MaineGuy]

I am converting my current set up so that my oil boiler will go cold. I have an owb (plan on getting a Garn Jr next year) with a heat exchanger and am converting from serial to parallel setup. I have a honeywell L8124A aquastat on my oil burner which controls one of my zones. (My system has a pump for each zone) The problem I am having is that the cirulator pump in that one zone won't active if the oil burner water is cold.
I figured out its a feature designed into the L8124A aquastat to allow the oil burner to catch up.

I believe I could just add another zone control relay (not use the zone control on the L8124A) so the pump works no matter what the temp is in the oil boiler. But I'm contemplating if I should do that or is there a control of some sort that I could replace the L8124A with that I can set up to recognize which system is needed. Like a control designed for primary and secondary heat sources?

The additional zone control would be easiest and cheapest but was just wondering if there's a better way to do this?

 

[Clarkbug]

Well, what other changes are you making to your system? Sounds like there will be some piping changes coming up in the future. Any anticipated changes in loads, zones, etc? That might help us figure out your needs long-term.

And you only have one of your zones controlled with this type of aquastat? Any particular reason why that might be?

Short term, can you just jump out the aquastat so that your circ runs when there is a call for heat from the t-stat? Thats even cheaper than a new zone control....

 

[MaineGuy]

Well, what other changes are you making to your system? Sounds like there will be some piping changes coming up in the future. Any anticipated changes in loads, zones, etc? That might help us figure out your needs long-term.

And you only have one of your zones controlled with this type of aquastat? Any particular reason why that might be?

Short term, can you just jump out the aquastat so that your circ runs when there is a call for heat from the t-stat? Thats even cheaper than a new zone control....

The L8124A is the aquastat that came on my oil burner. The system has a long history, it started out as a 2 zone system with an internal DHW coil when I had just my garage and an apartment I lived in upstairs. The oil burner was sized (btu wise) to heat this space plus a house addition which I added several years ago. I added the owb when I built the house since at the time the owb's were supposed to be the cat's meow. (They are fine in my rural area if you don't mind burning a lot of wood, which is free minus the labor to get it) The one zone that is giving my problems is the my original main heating zone that was hooked up the terminal on the L8124A.

Anyway to make a long story short 2 zones got added to the system for heat and 1 zone added for the indirect DHW system. The new zones were added via Argo single Switch relay's. So I have 3 of those now. Back then I had my boiler work done by a technician. Now I tend to do all my own work. I enjoy it and my former boiler tech who works for a commercial mechanical contractor who used to do residential on the side is getting close to retirement so he's not as excited about moonlighting. But he's a great resource and he always answers most questions I might run into.

So here's what I am planning to do after getting tired of looking at my eye sore of a boiler. There's piping and wiring going every which way, (mainly from expanding the system incrementally)

1. I just picked up a taco SR506-4 switching relay. I'm going to basically re-wire my whole system to try and simplify it.
2. Use one of the single zone controls (Argo AR822II along with a strap on Aquastat which I already have) to handle my zone valves to switch between the wood and oil system based on the temperature of the water coming in from the wood boiler. I've already got the piping pretty much done. The system is running right now but not very well. I had to partially open a manual valve to allow enough hot water into the oil burner to make the circulator run when the thermostat calls for heat. The zone that is acting up is now our bedrooms and my wife doesn't like to be cold when she sleeps I guess.
3. While I have my system drained I'm going to remove all the excess piping that's not doing anything.

I'm planning on maybe taking tomorrow off from work so I can get the re-wiring done and possibly finish my piping without being interupted by my wife and kids.

Fortunately I'm a designer/CAD operator by trade so I can draw up some pretty wiring diagrams before I start tearing stuff apart.

Sorry if this is a bit confusing I'm better at visualizing and showing a system than I am at describing it. I have an idea of how it all works in my head but may not always explain it correctly.

 

[peakbagger]

I didn't screw with my boiler controls, I just put a NC relay on the wire to the oil burner. When the wood boiler is above 140 degrees, the relay opens and the oil burner is locked out and the zones work like the oil was on. If the wood boiler drops below 140, the relay closes and the oil boiler runs normal. This worked well when I just had the boiler but when I added the storage things got a lot more complicated, basically if the storage is over 135 degrees and there is demand for heat in one of the zones, the supply wiring to the zone valve route the water from the storage instead of the boiler. Once the storage drops below 135 it reverts back to the oil boiler. I have it all hard wired with relays that "fail" in the right position when the power is turned off to the wood boiler so that the oil boiler reverts back to the way it was.

 

[MaineGuy]

I have a relay for my burner. But when my oil boiler goes cold, below 110 the lowest I can set my limit. It locks out one of my circulator pumps. The one that's hooked the oil boiler aqua stat. It does this so the oil burner will catch up. Except the oil burner will never fire so it does nothing.

 

[ewdudley]

I have a relay for my burner. But when my oil boiler goes cold, below 110 the lowest I can set my limit. It locks out one of my circulator pumps. The one that's hooked the oil boiler aqua stat. It does this so the oil burner will catch up. Except the oil burner will never fire so it does nothing.

;-)

 

[MaineGuy]

Problem solved. I pretty much rewired all my zones into one Taco zone control panel yesterday. Wow did that simplify things. It should be much easier to troubleshoot in the future. As well as added zone valves for bypasses to automate switching between the wood boiler and the oil boiler. I didn't end up using a zone control for the bypass zone valves, I was able to run both zone valves off the strap on aquastat on my the line coming from my wood boiler. Along with a couple 120/24v transformers I had sitting in my garage collecting dust.