Cold first morning shower

[jalmora]

I have a Weil-McLein Ulra 105 boiler and an Ultra Plus 60 indirect hot water heater. Installed 2010 in Anchorage, Alaska for a small duplex with 4 zones and 2 showers, hot water baseboard. I think home heating takes priority to water heating. Tenant, who takes a 30-minute high-flow shower at 6:00am (75-gal for a shower ?! everyday?!), said she is getting a 1-minute window of decent hot water, then it turns cold/lukewarm for the duration of her shower. Husband takes a shower 15 minutes later and says heat is fine. We shower after that and don't have any problem at all. I've tried to research how this could be the result of "cycling," but I'm not mechanical and haven't found a guide that makes sense to me. Could be there's a problem somewhere. Could be simply inherent to the system and I just don't understand it. Both sides have a programmable heating thermostat if that would force a cycle to occur at a time which would give her a hot shower at 6:00am, but like I wrote, I don't really understand the system to know if that's something that would effect it. Plumber is coming in 3 days to look at things. Any comments on the matter would be really appreciated. Thanks.

 

[Leon82]

Normally the domestic hot water would take priority. Unless the reverse is standard for Alaska.

I would think if she showers during a setback recovery it could struggle to keep up if the water heater doesn't have priority.

 

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[jalmora]

You're right, Leon82. Hot water has priority. I wrote that incorrectly in my post. So do you know if this should still be happening?

 

[Leon82]

There should be more than 1 min of water but tanks have different recovery rates.

Is there a nighttime setback for the water tank? You could set it to recover earlier and see what happens.

You may want to get up early and monitor what's going on one morning.