I had a loop added from the end of my hot water plumbing to the drain valve on my water heater many years ago. The system has worked great and I found I didn't need to use the pump to get the hot water to flow as gravity did the trick. I just had a new hot water heater installed and now the system is not working. Even when I turn the pump on I only get warm pipes with in a few feet of the pump which is about 4 feet from the drain valve on the bottom of the water heater. Any thoughts or ideas? We hooked the new water heater up just like the old. Thankyou- John

Have you unhooked the recirculating line and flushed it out? Sounds like you disturbed some mineral built up in the pipe walls and now it's blocking the line. Regards, tom

Have you unhooked the recirculating line and flushed it out? Sounds like you disturbed some mineral built up in the pipe walls and now it's blocking the line. regards, tom I haven't yet but I guess I need to prove I have flow through the entire run. I have 2 older gate valves on each side of the pump and one had to be closed very tightly with channel locks to get water to not flow. I am thinking it may have stuck. I will try replacing them both with new ball valves and somehow flushing the system. Thanks- john

The more I think about my problem the more I think that air is trapped in the last leg of the loop because there was no where to bleed the air off past the last open valve. I don't know if opening the valve that drains the water heater will bleed the loop or just allow water out of the heater tank. I will find out tomorrow. Thanks- john

Just opening the sink will bleed any air, sounds like the gate valve broke inside, I replace allot of them, always use a ball valve.
What type of water heater is it? Gas, electric, oil?

"I don,t know if opening the valve that drains the water heater will bleed the loop or just allow water out of the heater tank. I will find out tomorrow."

If you were going to bleed air out of a line the boiler drain isn't the place to do it. Air raises and the drain is located at the bottom of the tank. If you were air locked opening up a faucet would bleed off any air in the line. I hold by my original statement and check that gate valve, regards, Tom

"I don,t know if opening the valve that drains the water heater will bleed the loop or just allow water out of the heater tank. I will find out tomorrow."

If you were gonna bleed air out of a line the boiler drain isn't the place to do it. Air raises and the drain is located at the bottom of the tank. If you were air locked opening up a faucet would bleed off any air in the line. I hold by my original statement and check that gate valve, regards, Tom
I changed the gate valves out but they were working. I made a small adjustment and increased the water temp and that fixed the problem. I guess that the water needs to be hot enough to get movement in the system and on the lower setting it just wasn't enough. Now the system works great even without the pump.- Thanks for all your ideas.- John