Indirect Water Heater Help - Caber???

[Hooter]

Hi there,

I have a boiler system that also heats the water in my hot water tank (ie indirect water heater). I also have a hot water recirculating system to my second floor so that I get hot water pretty much instantly from any faucet upstairs. My problem is that when I get up in the morning to have a shower I turn my faucet on and get hot water, but within a minute or so the water gets cooler so I have to turn the lever to get more hot water. Then after another 30s to a minute then I have to turn the lever again. I have to keep doing this until I’m almost at maximum hot water, and then I can shower comfortably till the end of my shower.

My question is this: why do I have to keep turning the hot water up more and more to keep the temperature the same, then it stays at a comfortable temperature for 10-15 minutes once I’m nearly maxed out on hot water? FYI, it’s been this way since my house was built about 4 years ago. I’ve just put up with it till now.

Any help would be appreciated. Thanks.

Trevor

[CaberTosser]

Is it just at that fixture? For instance as a test, can you run that until it starts to drop temp and then go try the bathroom sink faucet to see it its also cooler? Sometimes the fault can be within the temperature balancing mechanism of the shower cartridge. Of course the heater will be the culprit if that faucet is also not as hot as you're used to.

[Hooter]

Sorry, I should have mentioned this before, but I noticed that all my faucets on the 2nd floor seem to require a constant adjustment to keep the water at a comfortable temperature.

I’ll do the test again just to be sure, though....more to come.

[Hooter]

So my bathtub seems to have the same issue. It’s like the water comes out quite hot for 10-20 seconds, then I need to keep opening the hot water tap to keep the temp constant until I get to where I’m at about 80% open with the hot water and then it seems to stabilize.

[CaberTosser]

Is the indirect heater you refer to a heat exchanger within a combi-boiler or are you talking about an actual indirect tank with storage that is piped to a boiler?

Sounds to me like a combi-boiler by what you describe happening

[Dewey Cox]

Is there a check valve on the return line of your recirculation setup?
If there's not, or it's stuck open, some water could be coming to your fixture backwards through the recirc leg, and that will be colder water from the bottom of your tank.