I just replaced the water softener as the membrane broke and I saw resin beads in dryer after doing laundry. Because the hot water heater was 10 yrs old, I had it replaced also. After the plumber was finished I noticed we weren't getting instant hot water to all faucets. The plumber came back out & said the recirc pump was only working intermittently. It is set to work 24/7. He replaced recirc pump with a new one. Both old & new are Grundfos. Sometimes we have to wait several minutes for a faucet or shower to get hot. Other times the same faucet or shower will be hot instantly. Help!

Is there a check valve in your system? Let me know, Tom

I don't know. I'm out of town & was going to call the plumber back over when I got home. Where would the check valve be & could the resin from the water softener have done something to it?

You should find the check valve near the heater if there is one.

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could the resin from the water softener have done something to it?

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If none of your faucets didn't clog then I don't think so. You should be able to feel the water coursing through the pipes all the time. If you don't and the pump's running then something's blocking the flow. I still like the check valve. Tom

Hi,

I work for Grundfos and may be able to help. Could you tell me the model of the pump? It should be something like "UP15-10SU7P" or similar.

Often when changes are made in the piping, a bit of air gets into the system. We have pretty tight tolerances inside our motors, so if air gets trapped in the pump, it needs to be purged because it can affect performance. Usually, all you need to do is run the pump for a few minutes along with a shower on the highest floor. Some models have an air vent on the motor, which makes venting really easy.

If there is resin in the system, then it may have gotten trapped in the motor as well, which might cause the pump to stop or overheat (if there's enough stuck inside). If that's the case, the motor can be removed, and partially disassembled to be cleaned - but if you decide to go that route, be sure that the pipes going to the pump are closed (isolated), so that you don't get sprayed with hot water.

Thank you for your help. I'm out of town but as soon as I get home, I will respond with the model #. I question that there was anything wrong with the original pump. It was working just fine until the plumber replaced the hot water heater and water softener. I know that there was a lot of air in the lines but there doesn't seem to be any now. The master shower is farthest away from the pump and has been used several times since the new installation. Sometimes this shower is hot and sometimes it takes a long time to heat up. But it's also like that with the other faucets as well. It seems very intermittent which is what it was doing before they installed the new pump but after installing the water heater and softener.