Replace Lochinvar Squire Indirect Water Heater with Tankless system?

[Phog]

Ok, good to have exact measurements.

For the recovery period you give after the showers ended, I calculate that out as somewhere between 94k-108k BTU/hr heat output from the boiler into the indirect (the range coming from whether your time period between temperate measurements was closer to 7 or to 8 minutes). Right around the 106k BTU/hr rating of your boiler, which also lines up with the 100% burner modulation on the display. Ok, things appear to be working correctly just as you say.

What's eluding me is this. In the 8 minute period your son was in the shower, the tank dropped 41F with the burner at maximum output. My math should be checked, but even at worst- case 32F incoming water temps, this requires something like 5+ GPM inflow.

Your daughter's shower, on the other hand, comes out somewhere in the 1.5 GPM range.

Did the kids use the same shower? Or perhaps did another appliance like a clothes washer also draw off the tank during your son's shower?

 

[eoren1]

Your last comment about 5 GPM flow made me realize something... Our new shower head has a rain head that puts out 2.5GPM. However, the kids' bathroom has a 10 year old rain head that I think does put out 4-5 GPM. We loved it when we used that bathroom but no reason the kids need that kind of flow and would explain everything.

Time for a new showerhead and a fix to this issue. Thank you!

 

[Sponsor]

 

[Dana]

Only 8 minutes? Did you pay him or something?

You'll probably be just fine when you crank the storage temp to 150F-160F and have the thermostatic mixing valve. I'm not sure how they got away with installing the indirect without any tempering or mixing valve (no inspector?), since it's been in MA code for a long time now. When I installed my own indirect in late 2008 it was a requirement, but I believe it wasn't a new requirement.

 

[eoren1]

Only 8 minutes? Did you pay him or something?

You'll probably be just fine when you crank the storage temp to 150F-160F and have the thermostatic mixing valve. I'm not sure how they got away with installing the indirect without any tempering or mixing valve (no inspector?), since it's been in MA code for a long time now. When I installed my own indirect in late 2008 it was a requirement, but I believe it wasn't a new requirement.

Well, he came out of the shower and was 100.9F (looked like crap going in).

And this morning, he's home and asked if it was okay if he took a shower and used up all the hot water...

Not sure about the mixing valve. We do have a strict inspector here. When we had the shower done in our addition recently, he wanted them to fill shower basin x 24 hours and used his own thermometer to check temperature of water.

I think the combination of a relatively low flow (2.5 GPM) head and the mixing valve will make everyone happy and be FAR less money than a separate tankless.

Thanks again - especially Dana and Phog!

 

[Phog]

Good luck!

One other thing to mention while we're on the subject of showers. If you have a tub/shower combo with a diverter faucet, keep the diverter in good working order. When they get old they can start to leak, aka the shower is going but there is still some water coming out the faucet and going right down the drain. It might seem like an inconsequential loss, but over 20 minutes it does add up.