Boiler piping change

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maplewoodshelby

Member
Mar 10, 2009
114
WV
Just finished my first winter with conventional wood/coal boiler. Things went very well and now that I have learned much about the system I'm looking to make it better.

My house is 3 levels. The downstairs den area and midlevel are on one zone and that thermostat controls the autodraft on my boiler. (house needs heat opens the draft). My pump kicks on whenever my boiler reaches 18o degrees so its not directly tied to the wall thermostat per se The upper floor where we sleep and where I had the biggest problem keeping the rooms up to temp has a seperate thermostat that controls a zone valve. When the upstairs needs heat it opens the zone valve and thus when the pump is running it sends hot water upstairs but also sends hot water to the rest of the house. The problem is that the downstairs and midlevel can be at a comfortable temp (thus keeping the thermostat satisfied and draft closed) while the upstairs is still needing heat. My solution this past winter was to keep the thermostat downstairs up high to keep the draft open which kicked the pump on more often sending hot water thru out the house. The downstairs did not get too hot but I feel like I need to seperate the upstairs and downstairs in a different way somehow to get the most out of my system. At night we all sleep upstairs and thats where I want the majority of my heat to go. In the daytime I need the opposite.

Any thoughts or suggestions on what you would do?

I have thought about a zone valve tied into the bottom floors thermostat thus when the bottom is warm it closes and send all the hot water upstairs. The problem is if both zones are satisfied I have no where for the heat to go.
I have also thought that I need my upstairs thermostat to also control the draft but the problem here is that if the upstairs says it needs heat and the downstairs says it dont then will it open the draft or not

This system has no storage and I am fairly maxed out at bitter cold temps heating 5000 sq feet but it does keep up. I just need to figure out how to get more hot water circulating upstairs.
On another not the upstairs attic is porrly insulated and that will be corrected this summer. There is also a 9 foot patio door upstairs that is very drafty that will be replaced this summer. So I'm also thinking not to mess with my system and see what those improvements do. Any thoughts would be appreciated

.
 
The solutions to your problems are really rather simple. Firstly the pumps, you can either get rid of the zone valve and put in a second pump or put in a second zone valve so the single pump runs when either zone calls for heat and the zone valves bring heat to either zone.

You will also need to modify your control system a little. This can be done with some inexpensive relays. You will probably need to have the autodraft come on if either zone is calling for heat and you will need to have the pump come on as well. I would suggest drawing up a diagram of the piping and controls for your existing system and posting it in this thread. Include the brand and model numbers of pumps and relays, etc. when possible and tell us what voltage your autodraft is controlled with. From there we can be more specific on exactly what you need to make the modifications.
 
Thanks for your input. I have tried drawing up diagrams and posting with little success. My system is quite simple so I can probably just word my way thru it.
I have an Energy King 45EKB wood boiler. It is piped directly into propane boiler which is never used. From there the pipe makes a 10 foot run and the two lower levels of the house piping tee of. This tee off pipe makes a loop around the 2 lower floors and reconnects into the return pipe a the same area 10 feet from the boiler.
Now back to the main pipe. It continues on for about 40 feet to a zone valve before heading upstairs and then looping back down and back to the boiler.
My lower floor thermostat controls the auto draft only. My upper floor thermostat controls the zone valve only.
The pump which is a Taco 007 is controlled only by the aquastat settings. The auto draft is 24 volt.
So as you can see my system needs some seperation
I'm thinking one pump with 2 zone valves is the way to go but my problem is if neither zone is calling for heat and the pump kicks on by aquastat the water has no where to go. How do I handle this.
Having the thermostat kick on the pump would probably not work in my case as I can not keep my water temps constantly high enough to have a on demand type setup that that would create. I like how the aquaatat runs my system and keeps my water temps where they are effective. Does this help any for suggestions
 
You basically need each thermostat to do two things. Each will open the zone valve and the autodraft whenever there is a call for heat. Luckily ZVs and the autodraft are both 24vac. So you need to have both thermostats run 24vac, and connect them first to their ZV and then have them connect to the autodraft. A problem may arise though with the current from one zone running back through the line of the other, inadvertently activating both zones when only one is called for. In that case it might make sense to put in some relays just prior to the autodraft so that the 24vac coming from the ZV (or thermostat) charge the coil of a relay instead of charging the draft fan directly. This would keep the two currents discreet from one another. For that you would need relays (SP or DP would do) that have a both the coil and switch rated for 24vac. These can be procured from Digikey, Grainger, or the like. Another option is to use some of these: http://www.energysavingcontrols.com...BU1C-RIB-Relay-Enclosed-10-amp-SPDT-P111.aspx . I have a brief article on relays that may help you understand how to utilize them in your system http://www.woodnotoil.com/articles.php?article_id=5 .

Edit: Another option might be to use two stage thermostats and you might be able to figure out a way to have the autodraft come on just before the room temp drops enough to open the zone valve. That way you wouldn't have to worry about using relays to keep the current discreet as well...
 
Great info. My father is an electrician and can help me with the relays. This is what I was thinking would need to be done but I still have the problem of what happens when the pump kicks on and no zones calling.
Even with my autodraft closed the temp will slowly kick up enough to overheat over a period of time
 
You could hook up a dump zone of sorts for that. You could even use your first zone as the dump zone. Again a relay could be used that would open that zone valve until the pump turned off again. That would dump the heat. Another option is to pipe a dump zone in where the boiler is (sized 10% of boiler output) or you could use an old water heater or something like that. The best place to dump the heat though is where it is useful. Yet another option is to put in a small amount of heat storage to even out performance just a little. This could be in the form of a small propane tank or even just some old hot water heaters plumbed in series. Lots of options to deal with the overheat situation...
 
Again thanks for the info. My setup is lacking a dump zone to begin with and that was in my future plans. I have battery backup for power failure but if a pump would fail I would be hurting The nice thing is that my boiler room is just off my garage and I could run the dump heat into the garage. It stays fairly warm now just by opening the door from the boiler room.
One more question. Would you still set this dump zone up with a zone valve and relays or go with an automag
Any particular brands you could recommend
 
couchburner said:
One more question. Would you still set this dump zone up with a zone valve and relays or go with an automag
Any particular brands you could recommend
Click to expand...

The automag is just a ZV that opens in the event of a power outage and allows thermodynamics to circulate the water to prevent overheating. Hooking it up that way is a good idea, but you will also want to be able to use it to dump heat in the situation you describe above where there is power and the autodraft is closed, no call for heat, and the circ kicks on. Perhaps a second set of piping with a normal ZV could be used for that situation and it could be set to open if the circ is on but the autodraft is not. Again that logic could be accomplished with relays.

Most ZV open up when charged. For the no power overheat situation you want one that stays closed when charged and opens when not charged. Automag is just one manufacturer of these. Others are available. Talk to someone at the supplier you go through and they can let you know what they have available.
 
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