I am installing zone valves but want to isolate each loop with ball valves. can I use regular plumbing ball valves for this. Max temp would be 180 F.
Plumbing – Do i need special ball valve for hot water heating system? Is WOG rating ok
plumbingwater-circulating-heating
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As longneck mentions this is a pressure reducing valve and this connection of the domestic cold water to your heating system is called the system make-up. It used to fill the system and to maintain the heating system's pressure. The knob on the top can be turned to adjust the system's pressure and should be done while the system is static.
However, a pressure reducing valve is not a cross connection device and should not be considered as one. While by its nature it creates a lower pressure on the heating side then that of the domestic side (therefore not allowing the water to back feed due to the pressure difference), if there is a drop of pressure on the domestic side (the required significance would depend on the domestic system pressure) or if the safety mechanisms on the heating side fail (such as the boiler fails to cut off and the pressure relieve valve fails to open) the heating side can result in a higher system pressure then that of the domestic side. This valve will not prevent back-flow in such scenarios. For true cross connection prevention you would need a double check valve or a reduced pressure back-flow assembly.
One last note: if you shut off the system make-up be sure to periodically check that the heating system maintains its set pressure. If the system drops too low you could cause damage to your heating source if it doesn't have built-in low water cut-off.
Here's a diagram of a hot water recirculating system
As I understand it, the idea here is that the recirculating system runs hot water around the pipework to keep the temperature hot near the faucets/taps. This allows for instant hot water at faucets/taps far from the water heater.
Even when no taps are running the pump should be actively maintaining the circulation as needed. It needs to do this as any unlagged pipes will cool the water in them if no faucets/taps are drawing hot water.
When the water near the faucets/taps is sufficiently hot, the "Aquastat" will turn the pump off.
Your power feed to the recirculating system should be via a timer, or other device, that lets the pump run whenever the "Aquastat" feels necessary. This should be "on" during any times of the day when you are likely to use the faucets/taps.
Some ideas:
- your timer isn't on or you are not allowing time for the pump to raise pipe temp.
- your "aquastat" is faulty.
- your "aquastat" is not near the faucet/tap you tried.
- your configuration needs additional "aquastats" or the "aquastat" relocated.
You should be able to test this with a thermometer and a voltmeter if you can locate the "aquastat"
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Best Answer
You're fine
Ordinary WOG (water, oil, gas) rated, metal-bodied ball valves are going to be rated for hydronic temperatures and beyond; if you want to make extra sure, you can check the specifications of the valve you're looking at for a WSP (Working Steam Pressure) rating, which a typical ball valve (using the Watts LFFBV as an example) will have as well. (Obviously, a plastic-bodied valve is going to have a much lower working temperature rating, and no WSP rating for that matter.)