# Plumbing crossover



## hvacdude

As my name implies, I'm an HVAC tech in Ontario, Canada (Gas Fitter 1 & 313A), I do mainly ICI work but do some residential work as well.
I've had a few residential calls on water heaters where the complaint is "not enough hot water" or "runs out after 1 shower". As a gasfitter, I can check that the combustion part of the water heater (tank or tankless) is doing its job. Usually that part is okay; the unit fires properly & there's a steady supply of hot water leaving the unit, but not coming out of the faucet (so the diptube in the tank seems okay to me). Once I verify that the combustion part of the process is not the problem, I usually tell the homeowner they need a plumber.
Rheem provided some info via their website on this condition - they call it "plumbing crossover" and they provide the steps to do to verify if it is (they say isolate the unit by shutting off the water supply, and go through the house & try all the faucets - if cold water comes out when the hot tap is turned, thats the problem). As far as I understand, its something to do with a mixing valve going wonky somewhere.

I don't want to get involved with plumbing issues, but I would like to know if I'm understanding the problem sufficiently to explain to the homeowner. So, am I understanding this "plumbing crossover" situation correctly?

Thanks in advance for any feedback anyone could provide on this.


----------



## PLUMBER_BILL

hvacdude said:


> As my name implies, I'm an HVAC tech in Ontario, Canada (Gas Fitter 1 & 313A), I do mainly ICI work but do some residential work as well.





hvacdude said:


> I've had a few residential calls on water heaters where the complaint is "not enough hot water" or "runs out after 1 shower". As a gasfitter, I can check that the combustion part of the water heater (tank or tankless) is doing its job. Usually that part is okay; the unit fires properly & there's a steady supply of hot water leaving the unit, but not coming out of the faucet (so the diptube in the tank seems okay to me). Once I verify that the combustion part of the process is not the problem, I usually tell the homeowner they need a plumber.
> Rheem provided some info via their website on this condition - they call it "plumbing crossover" and they provide the steps to do to verify if it is (they say isolate the unit by shutting off the water supply, and go through the house & try all the faucets - if cold water comes out when the hot tap is turned, thats the problem). As far as I understand, its something to do with a mixing valve going wonky somewhere.
> 
> I don't want to get involved with plumbing issues, but I would like to know if I'm understanding the problem sufficiently to explain to the homeowner. So, am I understanding this "plumbing crossover" situation correctly?
> 
> Thanks in advance for any feedback anyone could provide on this.


 

Yes you are on the right track, the biggest culprite in faucets was Moen with the old 1220 cartridge. However any selonoid valve controlling hot and cold water [like a washing machine] could also cross over. Had one, one time with two boiler drains in a green house. Owner was raising catus and needed tempered water for irigation. He bought a hose wye connector and hooked to his boiler drains. So as not to have to adjust the temp all the time he fabricated a valve at the hose end. No checks were installed! Our service call was for no hot water anywhere in the house except he had tempered water in the green house.


----------



## RealLivePlumber

Handyman/general contractor yesterday, Hvac guy today. 

What is this place coming to?


----------



## SlickRick

Not a plumber, but he is a gasfitter. Stay or go?


----------



## Titan Plumbing

Oh crap, not this argument again.............Wait for Scott, he'll tell ya!


----------



## Scott K

Titan Plumbing said:


> Oh crap, not this argument again.............Wait for Scott, he'll tell ya!


Hey DUDE, did I say it was ever inappropriate for a plumber to have his gas ticket? Or an HVAC guy to have his gas ticket either? My case is to have just a simple heading that says gasfitting in this forum, or a seperate forum. 

I say get as many tickets as you can. The more tickets and knowledge you have, the more valuable you are assuming you do more than just take schooling but actually gain some practical experience to work with those tickets. In this case, a Plumber who also has his or her gas ticket as well (or in your case, perhaps your state has included their gas ticket as part of their Plumbing Ticket) would be invaluable to troubleshooting the problem mentioned above. 

As to whether he can remain in this forum or not, that's not my call. At least he is a professional who cares about his customers and is treading water right now asking for our opinion. Any guy who is willing to ask for help is committed to doing it right and that's a pro in my books.


----------



## Epox

Titan Plumbing said:


> Oh crap, not this argument again.............Wait for Scott, he'll tell ya!


LOL and it begins


----------



## Titan Plumbing

Okay, Okay..........


----------



## hvacdude

Plumber Bill: Thanks for the confirmation. Like I said, I don't want to even begin getting involved with anything resembling a plumbing issue (which I consider this "crossover" condition to be). I'll just keep doing as I've been doing & advising the people that they need a plumber to properly resolve this type of problem. Now I can also refer people to a good plumber that I know of - how much for a service call from Allentown PA to Toronto ON???

Thanks again for clearing that up for me.
Best wishes for a safe & happy New Year.


----------

