With two separate thermostats and two different rooms, I'd prefer to see a setup like the one below. It's certainly not the only way to do it. But it's fairly simple: Hopefully you can sort of reconcile what you have with the bits and pieces in the schematic. Again, you might not have all of them, or you might have more. And the bits and pieces don't have to be in the order or in the locations I have them. I'll start by writing about the shutoff valves. There are several in the schematic. They bracket some of the bits and pieces to allow maintenance on your system. Example, if you have to replace a pump, you can isolate the pump by turning off the shutoff valves on either side of the pump. If you have no shutoff valves, when you pulled the pump out of the loop, you'd lose all the water in your system. I prefer full port valves for shutoff. The photos are just for reference: So you have the water heater. Hot water comes out of the water heater and flows through a check valve. That valve prevents backflow or reverse flow through the water heater. Typical backflow valve: The pressure gauge allows you to monitor the pressure of the water in the system. I usually run closed systems at about 12psi of water pressure. After the pressure gauge is a "fill" hose bib. Just like a garden faucet hose bib, though you can certainly use something better. There's normally a hose connection down low on the water heater. You connect a garden hose to the water heater bib, open the "fill" hose bib, and fill the system with water. Or a water/glycol solution if you need freeze protection. After the fill bib is the expansion tank and the air eliminator. Since it's a closed system and water expands when hot and contracts when cool, the expansion tank allows the system to absorb those changes in water volume while allowing the system pressure to remain constant as 12psi. Expansion tank: Air eliminators have a couple of different looks: or this: To the right of the expansion tank is another "fill" valve that has a cold water supply plumbed into it. That's a pressure compensating valve set at, you guessed it, 12psi. If the system pressure drops below 12psi, that valve automatically opens and recharges the system to 12psi. The little lever on top allows you to add water manually. The valves are usually pressure-adjustable. I just happen to use 12psi as my setting. Why would you need to add water to a closed system? The air eliminator "burps" air from the system. Air in the system can cause turbulence noise when the water flows, a large bubble could cause flow problems or pump problems. So the air eliminator eliminates air. But sometimes water can dribble out too. So if/when you have water loss, the 12psi valve will recharge the loops with water. The "Temp in" gauge shows the water temp as it enters the loops. Usually about 120 degrees. Maybe more or less. Then the system branches off into two zones, one for the bathroom, one for the sunroom. Each zone has its own circulating pump. When the room's thermostat calls for heat, the circulating pump kicks on and circulates hot water through the zone and to the loops in the zone. Typical Taco pump: You can add a Grundfos Alpha pump. Very energy efficient: With two pumps, the rooms can be heated individually or concurrently. When the water returns from the zone(s), it goes through another temperature gauge. You can compare the Delta T or the change in temp of the water to see if the heat is being given up to the rooms. "Temp In" minus "Temp Out" equals Delta T. And there you go. Again, each zone can simply be a single loop of PEX. Small rooms can sometimes be served by a single loop that is on it's own zone. If the room is large and you need more PEX, then you can install a manifold for that zone and you can have several loops on that manifold. Again, each loop should only have about 225' maximum of tubing in the loop. If a room needed 350' of tubing, I'd split it into two loops of 175' each instead of a 225' loop and a 125' loop. Example of a four loop manifold, this manifold has the "temp in" and "temp out" gauges built in: That's a basic system with no real automation.

>> Hope to hear an update from the original poster of the thread soon as well. Hi, still here. :) Yeah, so far, none of the contractors have proposed a 'mismatched' coil and condenser. One said 5/5, but all the others have been 4/4 so far. No load calcs yet. One contractor said he'd do it if there were a commitment to go with them. So if they commit to dropping their price and changing some of the equip to match better proposals from others, then we may have something.. :) [unfortunately, although they had a polished sales presentation, their bid missed a couple elements with regard to equipment, including the low voltage wiring and the mismatched coil size (width)] I did see that the 4-ton XL15i requires the 7/8" x 3/8", so looks like I'm good. (phew) A contractor on Friday also said I'd need additional wiring to hook up a heat pump outside, so looks like it was missed by the one proposal. I think this has been asked before, but is the TL900 the same as the VisionPRO IAQ? I have two more contractors coming Monday, so after that will hopefully have all the information I need to start discussing it further with 1 or 2 and start negotiating equipment and price details. On related topics: There have been other differences in proposals, with some suggesting/including a replacement condenser pad, some not. I currently have what looks like an interlocking plastic condenser pad. Doesn't appear damaged, although may be slightly out-of-level (will be checking to make sure). Surrounded by bushes that I keep in check, and mulched w/ weeding done when needed. I understand concrete is the best option, but doubt the pads being included in some of the bids are much better than what I have. I'll be doing my own check to confirm what I have would fit the new condenser/heat pump. And, some are including an Electrical Disconnect/Fuse rewiring, some not. There's currently a disconnect (no fuse) connected to a 40amp double pole circuit breaker. One guy told me "that should be enough, but if it isn't and it trips a lot, we'll fix it free of charge" or something to the effect; which I'm not sure whether it's a good deal that he's not trying to sell me something I don't need or a caution flag that he doesn't know if it's sufficient.. The XL15i documentation says "Min Cir Ampacity = 30" and "Max Fuse Size (Amps) = 50", so I'm not sure whether that means the 40amp circuit breaker is sufficient or not.

I received the following quote below for an 1200SF house and I live in MA. The quote is for re-doing the entire system from 'ugly octopus' to high efficient furnace! can someone tell me if this sounds reasonable for the cost? I have additional quotes coming in but am not sure what to expect... thanks! Price Includes: Bryant High Efficiency (95%) Gas Fired Furnace  New plenum and return set up with EZ Change Filter Rack  All Ductwork required (re-hung and layout configuration)  New Return Boxes  All PVC venting required  All gas plumbing hung and secured  All high and low voltage wiring  New 5-2 programmable Variable speed thermostat  Condensate pump and drainage  Removal of existing furnace and oil tank  Termination cap for exhaust and supply combustion Total Parts and LaborÂÂÂÂÂÂÂÂÂÂÂÂÂÂ$9,600

I'm knee deep in tools and measuring devices, but at present only have a manometer (BAFO, I vaguely recall) that converts differential pressure to current for my future active MUA. It is installed to measure kitchen pressure vs. exterior pressure. Because the latter is very difficult ($$$) to do accurately in the presence of wind, its exterior port is physically in my heavily ventilated attic. Having a separate manometer to measure pressure drop across my baffles would help clarify what their pressure drop is as a function of air flow, which I can measure now. Good suggestion. Keep in mind making pressure measurements implies that one can access the two measurement points. My heat exchanger is several inches above the diffuser, so I'm not sure that the flow straightening of the exchanger is all that helpful to minimizing turbulence down the hall approaching the hood, but it may help. As I believe I previously noted, control for the hydronic loop can be fairly simple -- at least a lot less complex than control of the MUA flow rate over the hood flow variability, along with whatever other household exhausts one deems worthy of being compensated. If one were so motivated, a proportional control of the hydronic pump could be configured to better regulate the output air temperature. Probably better with zone valves would be to duty cycle the open time vs. temperature error. My present boiler system replacing a Weil-McLean with a batch of zone pumps is a System 2000 with a batch of gate valves, and its controller has its own opinion of how to operate. Thus, any meddling by me has to be done externally and "expressed" via the thermostat interfaces.