Water heater in series or so I thought...

[ajohansson]

new house to me and have been working through some plumbing stuff with all of your help!

So put in my mixing valve this weekend. I have 2 water heaters. I assumed in series as the cold water inlet into one of them is hot all the time. The other water heater inlet is cold on the cold side which has the inlet shut off valve. The plumbing stubs out of the wall so its not like the hotwater heaters are jumped one to another on the exterior with all plumbing visible.

So heres the thing. I turn both water heaters to pilot, drain the hot water lines and put in the thermostatic mixing valve.

I turn on the second in series water heater to try out the mixing valve. I left the first one off because i had to repair some of the flue vent and didnt have any metal tape.

I go to the faucet check the temp and its 118 im happy as the water heater is at 140. Then my daughter comes down and says i have no hot water. Im puzzled and sure enough her bathroom sinks and shower has no hotwater. All other baths and sinks etc etc have hotwater in the house.

So i get the flue fixed and fired up the first water heater and she gets hot water and the inlet to the second heater is now warm.

So im thinking the first water heater goes into the wall and must T up to daughters bath which is directly above on the next floor and then stub out to the cold side of the second water heater.

Why would anyone do this? Is there an advantage? Now if i want to really protect all the fixtures i have to get another thermostatic mixing valve.

Any thoughts on why its plumbed this way would be helpfull.

AJ

 

[Reach4]

Why would anyone do this?

speculation...

Speed up the daughter's showers? Give priority to other showers? Allow the daughter's shower to be set cooler in pre-mixer days?

 

[Sponsor]

 

[ajohansson]

Yeah perhaps just weird that one water heater would serve one bathroom and T off to the other heater. There are 3 other full baths in the house for a total of four. Seems
Like you would split the baths up. In any case thanks for your reply looks like i need another mixing valve to keep her hotwater at a safer temp.

 

[Reach4]

Yeah perhaps just weird that one water heater would serve one bathroom and T off to the other heater. There are 3 other full baths in the house for a total of four. Seems
Like you would split the baths up. In any case thanks for your reply looks like i need another mixing valve to keep her hotwater at a safer temp.

You could move the pipe. I would be nice if you could feed the washing machine and dishwasher with unmixed hot water.

 

[hj]

We have no assurance that your diagnosis is correct. There may be factors that you are not telling us. If the heaters are in series, it is usually to enhance the hot water supply from the second one and the tempering/mixing valve should have been on the first one.