Yea so I had my installer back today because I was in parallel and the OB was not acting as a backup. I first ran him through my idea of putting a circ in between the two boilers as well as a zone control to prevent the zone from running during boiler to boiler heat. He didn't like that and decided that series installation was what would fix my problem. (problem being OB out of the loop, unable to take over in case of failure, as well as PB not bringing it up to temp). I argued my point for a minute but he insisted that in series (out of PB to in of OB, out of OB to zone) that the hot water sitting in the PB would heat the OB just by gravity or whatever. So now its all hooked up in series and the PB won't pull the OB past 150. If i turn the high setting on of the OB to 180 (where it should be) it runs untill it pulls itself up to temp. Uuuugh. At least now there is actually water flowing through the OB though? lol
PB-105 RE-Installation
- Thread starter Wayne64SS
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Are you saying, when the zone has a call for heat, the zone circulator starts bringing return water from the zone to the PB which pushes the heated water out the supply of the PB to the return of the OB, out the supply of the OB to the zone?? Maybe I'm misreading what you have mentioned.
This what I have and it works for me.
Today I have the PB set at 175 min and 185 max. Feed rate 6
I have the OB set at 130 max 110 min.
The PB is my primary, if it should fail the OB takes over and heats the house till I can get the PB back on line.
When it was in the 40's and above I had the oil controls all the way down to their min, effectively off,
and the PB set at 140 min and 180 max and I let the PB and outside air temp decide what temp would be set in the boiler.
If you have a domestic hot water coil in the OB then you may want a circ set up between the OB and PB so to keep the 2 at the PB 105 temp.
Today I have the PB set at 175 min and 185 max. Feed rate 6
I have the OB set at 130 max 110 min.
The PB is my primary, if it should fail the OB takes over and heats the house till I can get the PB back on line.
When it was in the 40's and above I had the oil controls all the way down to their min, effectively off,
and the PB set at 140 min and 180 max and I let the PB and outside air temp decide what temp would be set in the boiler.
If you have a domestic hot water coil in the OB then you may want a circ set up between the OB and PB so to keep the 2 at the PB 105 temp.
yea i do have a dhw coil in the OB but i dont use it. do you have a circ in yours or does the pb keep the ob at temp without it? if i put a circ in i would have to put in a bypass right? so it wouldnt flow to the zone? any help would be appretiated. thanks.
I don't have a circ and it seems to work OK. I keep the PB temp up and the OB temps down. I have a 4000 sq ft house so some zone is calling for heat often enough to keep hot water in the OB. I did have to experiment with the temp on the OB. I had to keep lowering it to avoid startup of the OB when there was a high demand on the PB and its temp dropped.
When its warm outside I use the OAT option on the PB and have its low temp set at 140. Thats why when its in the 40's and above I basically turn off the OB by turning its control to the lowest settings.
If I did ever put in a circ. It would be a 3/4 inch line with a taco 007 pump. It would go from the distribution manifold over the OB staight to the return manifold. Since I am in series water would flow from the OB to the return of the PB and then from the output of the PB to the return of the OB equaling temps. I would use a strap on aquastat that uses line voltage switching on the output of the PB to control it, set to the just below the min temp of the PB.
When its warm outside I use the OAT option on the PB and have its low temp set at 140. Thats why when its in the 40's and above I basically turn off the OB by turning its control to the lowest settings.
If I did ever put in a circ. It would be a 3/4 inch line with a taco 007 pump. It would go from the distribution manifold over the OB staight to the return manifold. Since I am in series water would flow from the OB to the return of the PB and then from the output of the PB to the return of the OB equaling temps. I would use a strap on aquastat that uses line voltage switching on the output of the PB to control it, set to the just below the min temp of the PB.
sweet i think that is the way im gonna go too. ill post back when i talk to my installer.
you need a zone controller though so that the water doesnt flow through the zone while you are circing through just the boilers right?
you need a zone controller though so that the water doesnt flow through the zone while you are circing through just the boilers right?
I don't think you need a controller.
Line voltage goes to the strap on aquastat then to the circ.
Water goes from the supply to the return.
Water can't go to the other zones because check valves.
Oh I would also put a check valve in before the circ.
Line voltage goes to the strap on aquastat then to the circ.
Water goes from the supply to the return.
Water can't go to the other zones because check valves.
Oh I would also put a check valve in before the circ.
IMO, I think it would be a big plus for you to use a circ between the boilers to equal temps in both boilers, although you will have some heat loss from the OB out the stack when doing this. The plus is you will have storage capacity of heated water to meet the demand for heat, circulating hotter water to satisfy the demand for heat quicker. I have mine piped like the drawing for parallel piping on page 16 of the owners manual, difference being a circulator in the return at the PB.787MH said:
wil said:
Hey Wil,
Wayne and I had the same installation originally (by the same guys) and have (had) a circ in line between the returns but this was our "over heat" circulator, meaning it was hooked up to the PB "aux output/overheat zone and would only come on if the PB went over 220 degrees (?). The manual shows this circ nowhere and the only mention of it that I can find is on the wiring diagram ...and the manual states "if used".
Well, basically, if I'm understanding how you have your system set up, this would be the circ that runs off the aquastat on your OB, right ? I'm thinking that I'm going to install an aquastat on my OB and hook that into this circ. Just not sure where (if at all) I'm going to hook up my "overheat zone"...maybe to a relay that turns on my zones that way the water would actually have somewhere to go.......
Thats correct. I don't have a overheat zone, but if I decide one day (after the relief valve releases and wish I did) it will be quite easy to do for me because I have a unit heater in my work shop to make into a overheat zone. In your situation, all that would be needed is some piping to bypass the flo-check on the zone, use a zone valve to open, controlled by the PB controller.
Hey Sting,Sting said:
Great idea, simple, just use the existing zone circulator with a cube relay controlled from the PB controller.
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