New Heating System Issue/Questions

Badbisco

Hi,

Bought a house recently and running into an issue and wanted to see if the experts had ideas. Waiting for a response from the guy who installed it. I'm a non-handy person and limited understanding of all this so please excuse any wrong terms or ignorance of basics.

System Details: 5,000 Sq ft house in Maine, 8 heat pumps/mini splits plus an oil boiler and HW baseboards. Buderus Logano G215 is new, 3 months old, set up in 5 baseboards zones and 1 indirect zone for the HW heater (Bradford White with a separate Grundfos Comfort PM circulator?). 5 baseboard zones have Taco 007e circulators and 1 indirect has a Taco 0018e circulator, all running with a Taco SR-506-EXP switching relay. System also has a Taco piece detailing outside temp (47 degrees F), assuming this regulates the temp of boiler supplied HW to system.

Taco circulators are all set up on end of individual return pipes feeding into a header returning them all to the boiler (believe its the boiler return based on Buderus diagrams, sits below other pipe I believe feeds supply to header pipe with individual zones and HW branching off it.

Goal: Limit use of oil heat until needed based on having more efficient heat pumps/mini splits.

Issue: When we recently had 500 gallon oil tank filled, it seemed more oil than just for periodic firings for HW heater was used. They had it filled completely earlier this year and we refilled it 170 gallons in Sept.

Then, just now all baseboards starting pinging and getting slightly warm despite all Thermostats being set to Off. Checked system and no baseboard Taco circulators were lighted/on except for the indirect zone feeding HW heater. Supply header was hot and individual baseboard supply pipes were relatively hot. All return pipes were relatively hot/warm not just the HW return.

Obviously hot water was traveling into the baseboard zones when the HW heater calls even though the thermostats for every baseboard zone is off. I'm guessing having some heat from the HW running through shared header to HW heater may warm the baseboard supply pipes but to the degree the baseboards are pinging surprised me.

Questions:

Is this normal?

Are the Taco circulators always on the return pipes? (I'd assumed they would be on the supply pipes to each zone but suppose the physics of pressure may make it not matter in terms of which end they are on)

My main concern is that firing for HW heater is leaking into zones when we want off to conserve oil.

Thanks and appreciate any thoughts!

SuperTech

Ideally the circulators should be on the supply side of the boiler, pumping away from the expansion tank and air eliminator. But systems have been installed with pumps on the return for years and worked just fine. That's the old fashioned way of doing things. Each baseboard zone should have a flow check valve on the supply side to prevent the gravity circulation you appear to be experiencing. Can you post a picture of your boiler and piping? That would be helpful in figuring out the cause of your problem.

Badbisco

Pictures

SuperTech

Ok, you have a great boiler and the installation looks good. I like the use of the Spirovent air eliminator. The pressure reducing fill valve is piped to the air eliminator location, this is good. I can tell from the picture where the pipe from the expansion tank goes to, it goes to the same location as the fill valve, that's good. But none of that is your problem.

What I don't see is any flow check valves. Typically they are on the supply pipes at the top of each of the first vertical pipes coming from the boiler. Usually red or green in color. Do you have anything there or do you just have copper 90⁰ elbows?

Do any of the circulators have flow check valves inside of them? Usually they will have the letters IFC in the model numbers. I believe this stands for internal or integral flow check.

Badbisco

Thanks, taking daughter to appointment and will check/report back later. Appreciate your time

mattmia2

Sometimes they come with the flow check loose in the box and a sticker you can put on the circulator when you install it too. Sometimes you can get away without the flow checks on the supply if you have them on the return but you can get enough 2 way convective flow within the supply pipe to partially heat the zone.

It is possible that if the circulator for the indirect is too big or the piping is too small that it may push flow through the flow checks.

Badbisco

Hi,

Just 90⁰ elbows at top of vertical supply pipes to each zone.

Indirect circulator for HW is https://www.supplystop.com/products/0018e-2f4-ecm-var-speed-c-i-circ-universal-flange-120-v-bluetooth?srsltid=AfmBOoohnA107zkRKbaWEu9KeS74aQxtMvu6XjsTkO5WJHkNovRVGlfu

which lists "Integral Flow Check (IFC) included - Field installed". This has Proportional Pressure, Constant Pressure, and Fixed Speed settings. It's currently set to Bluetooth and I need to get the app so not sure which it is on.

Baseboard circulators are https://www.supplyfile.com/docs/taco/007e_Catalog_100-150.pdf

which list "Integral Flow Check (IFC®) included"

SuperTech

The IFC would probably be more effective if all the pumps were on the supply. It's possible that they can't hold back the gravity circulation from the mass of water in the boiler and piping. I can see one or two of the IFCs failing or something getting stuck in them but not all of them. Probably the easiest thing to do is have your service provider remove the IFCs and add typical Taco or B&G flow check valves in place of those 90⁰ elbows on the supply pipes.