Zone returns hooked in wrong place??

i didn't plumb in coal boiler, but i know from performce the zone returns are hooked into wrong side of system. zones are feeding back into supply to oil boiler, which suppies to zone feeds. Therfore its mainly recirculating the cooled return back into the main supply to oil boiler.

Am i correct?

i drew this up quickly... there are a few minor errors, but my primary concern is where the zone return lines are NOW hooked in. I told the installer, returns from zones need to be in line goint to circulator that goes back to coal boiler, not into the main supply line between the coal boiler and oil boiler.

ya it looks like the piping lay out is not the way you alledgedly told him to pipe it , but why are you telling us ,did you have a signed contract ? did he pull a permit? you should have some recourse! have you contacted him? perhaps he would come back and put it the way you requsted if you were to ask him, it will work the way it is but its like taking the dip tube out of a water heater .

yes i get heat, but no reason for oil boiler to kick on and heat water, and it does to recover the heat load. Only reason i see is, thez one returns are tempering down the 180* water from coal boiler. No contrat, but he hasn't been paid either. There should be no reason for oil boiler to run if 180* heat from coal boiler is going to oil boiler.

He said theres not enough base boards for house. Never had problem heating house on 180* water before with oil boiler. water temp going to baseboards determines BTU output of baseboards.

The problem with the way it is hooked up is that the hot water from the coal boiler is being blended with the water returning from the zones...so you end up with "tempered water" going back to the zones. That may or may not matter depending on what your home requires to stay comfortable, but if the oil boiler is still online and set at 180 degrees...it will fire when the zones first circulate. When I moved into my house it had a hand-fed boiler that was hooked up the same way...and I had the same problems you are experiencing. When I installed my EFM, I swapped the supply and return so the hot water leaving the EFM goes directly into the supply header.

simple fix

wire the TT terminals of the triple aquastat on the Oil Boiler to a new tstat in the house and set that to 50 degrees

THERE

now the OB will not fire until the coal boiler fails and the house gets cold

only draw back is that of a series boiler system and thats not a big drama

Kind regards
Sting

i have my coal boiler and gas boiler isolated at the supply by a zone valve on each boiler. the coal boiler is the lead with gas as the lag, with an immersion temp control on supply of coal boiler to select zone valves. end switches on each zone valve are in the control circuit for the respective boiler. zone valves offer migration isolation for the off boiler and aquastat isolation.

thinking about "T" in by oil boiler return, reroute coal boiler feed/supply to T at oil boiler return i put in,have a ball valve in coal boiler feed to oil boiler, and have ball valve in other leg off T which will still go to return zone mainold. Run other side of zone return manifold(was feed from CB) go to return side of zone (feed) circulator manifold ahead of the coal boiler return circulator. During coal heating season, keep ball valve from T by oil return to zone return manifold closed, and ball valve off same T to coal boiler supply open. Summer reverse positions of the same to ball valves and run oil boiler seperated from coal boiler. there are shot off ball valves at coal boiler main lines to isolate. Circulator that feeds return to coal boiler does run 24/7 during heating season so water between the 2 will always be circulating.

This is only way i can see to get direct coal boiler hot water into oil boiler, and not have to run oi lboiler of a TT, keep zone returns from tempering coal boiler supply, and will get me thru remainder of this winter.

wilder11354 wrote:t Circulator that feeds return to coal boiler does run 24/7 during heating season so water between the 2 will always be circulating..

Well - you certainly do have a hybrid heating system.

As long as you simply limit the oil boiler on time, by changing the OB call to fire sequence- well your half way thru the season -- let it ride -- a simple wire in as I suggested will do for now

Read what a true primary secondary piping system is - and how to employ hydraulic separation

Don't blame the lowest bidder that you hired and instructed incorrectly

Sting wrote:

wilder11354 wrote:t Circulator that feeds return to coal boiler does run 24/7 during heating season so water between the 2 will always be circulating..

Well - you certainly do have a hybrid heating system.

As long as you simply limit the oil boiler on time, by changing the OB call to fire sequence- well your half way thru the season -- let it ride -- a simple wire in as I suggested will do for now

Read what a true primary secondary piping system is - and how to employ hydraulic separation

Don't blame the lowest bidder that you hired and instructed incorrectly

I did limit boiler on time, unplugged the burner head. As far as instructing the plumber as what to do for plumbing it in, i didn't tell him how to hook up plumbing. He's been doing boiler installs service work all his life.