DHW mixing valve malfunction?

pcloadletter

I have a Peerless EC/ECT boiler with a DHW coil and a Watts 70A mixing valve. Over the past year I've noticed the hot water temp steadily decreasing, so last month I replaced the innards of the mixing valve. I couldn't get the rebuild kit locally so I just picked up another 70A valve and swapped out the parts. This helped a little, but my hot water temp is still only about 125 coming out of the kitchen faucet on full hot with the mixing valve turned all the way to 160. The kitchen faucet is only about 10' from the boiler and the hot water pipes are all insulated. The kitchen faucet has a water saving aerator on it so it's not pulling lots of GPM like a tub spout would.



I'm thinking that even if my hot water coil is restricted, when using a low-flow faucet I should get at least 140 degree water, right? This is assuming the mixing valve is working correctly. Or does a clogged coil limit the water temp regardless of the flow rate?



I have city water so it's not like my water supply has a ton of minerals to clog up the coil. Flushing the coil would be a pain in the butt for me because mine is connected without unions so I would need to unsolder some copper to hook up hoses.



PS - What's the difference between the Peerless EC and ECT? A tankless coil?



Thoughts?