Thanks Dana for the explanation. The valve is set to full open, and the system has been working so I won't mess with it.
I'll pop the cover and check for more info.
Do you have any reservations on using this system for year round use? Any recommendations on upgrading?
Using the system year round would be fine- just expensive to operate.
As for upgrading...
Rather than spending the money on a propane boiler,
cold climate ductless
mini-split heat pumps sized to carry most or all of the load in the bigger more open zones will use only about 1/3 (or less) the electricity of the electric boiler. Even at CT style electric rates (among the highest in the US) , heating with high efficiency mini-splits is substantially cheaper than heating with condensing propane. The mini-splits also dehumidify and cool at high efficiency, something a propane boiler can't do.
Air sealing and insulating the basement to at least the code-minimum R15 continuous air impermeable insulation (or R5-R6 continuous foam trapped to the foundation with 2x4/R13 studwall) is cost effective, even if heating with heat pumps or propane. I looks like you might not be able to get the full R15 without gaps without revising the boiler mounting & plumbing, but that's fine. Most of the heat loss is the above-grade portion, most of the air leakage is at the foundation sill & band joist. If there's 50 square feet left uninsulated it's still WELL worth insulating the other. Even a 50F unheated basement can be a HUGE heat loss, typically on the order of 15-20% of the total heat load of an otherwise reasonably insulated house, sometimes more.
There are
multiple foam
reclaimers in southern New England trading in
used roofing foam at typically <1/3 the cost of virgin stock goods, and some carry virgin stock factory blemished sheet foam for <1/2 the cost of perfect goods. At 3" most 2lb fiber faced roofing polyiso runs a true R17-ish in performance, and can be mounted to the wall with 1x4 furring through-screwed with 4.5"-5" masonry screws, mounting the wallboard on the furring. With used foam this is cheaper than a hybrid 2x4/R13 + R5 c.i. solution using fiberglass batts and box-store 3/4" polyiso. There some details to get right with either approach. If interested I can go into it further here, but there are multiple threads where it has been covered it in the past.
Insulating the heating system plumbing with at least 1" fiberglass pipe insulation wherever possible is also cost effective, where possible. Don't use cheap thin-walled fiberglass, and don't use foamed polyethylene on any heating system plumbing (but DO use the foamy stuff on all the accessible potable hot water plumbing, and even the 10' of cold feed nearest the water heater.) Box store fiberglass pipe insulation is overpriced and not thick enough. Plumbing supply houses usually carry a selection, but there are web-stores with the right stuff available too.
Before updating any of the heating equipment, run a careful room-by-room heat load calculation using aggressive (rather than conservative) assumptions about R values & air leakage rates. Most load tools overestimate reality by a double-digit percentage, and oversizing either a fossil-burner or a mini-split reduces both comfort & efficiency, and costs more up front.
If you have been using the house continuously this winter you're in a position to run an e
nergy-use based heat load calculation to put an upper bound on the whole house heat load. If there is enough baseboard that it's been able to stay warm, the boiler's output temperature and total feet of baseboard establishes another (usually much higher) upper bound. If the room-to-room temperatures have tracked reasonably close to each other, the amount of baseboard per room on each zone (looks like two zones?) can tell you roughly the proportionate room loads, which should roughly track the
Manual-J or
I=B=R type room by room load number proportions, but the baseboard lengths can't tell you the total heat load.
Do NOT leave the load calculations up to an HVAC pro! The track record of the industry is abyssmal. They make their money by selling and installing equipment, and are overly conservative in their load calculation methods, opting to avoid the 5AM call from the shivering irate customer on the coldest night of the heater at all costs (your costs.) If using a third party for that service, use a registered professional engineer or RESNET rater, someone who makes their living and reputation on the accuracy of their numbers. In my neighborhood that service runs between $500-1000 for a decent sized house with a dozen or more rooms, but it'll usually save you more than that just in the cost-adder for oversized equipment.
