Problem with hot water heaters. I think.

[Ladycfp]

I purchased a vacation home in a resort community in December. Home inspection clean. First clue, I noted that water coming out of cold tap was not really COLD, throughout home. Water bill arrives and it is a whopper. Utility company confirms this a usual bill for home. Prior to our purchase, home used heavily as short term rental, but we are there few days a month at best.

Handyman hired comes out rules out leak between home and water line by turning off water to home and monitoring meter throughout day. We then check toilets for leak and in turning them off I notice several of them handles on shut off warm to touch and water in bowls is also. Handyman decides several toilets leak and replaces fill valves in them. Also installs check valve in hot water heater (there are two tanks.) He mentions it could be bigger problem but this might work.

The water bill after toilet repairs is normal again ($35 for a month instead of initial $200) but warm water at cold taps persists. I have also noticed by now when I am there that the hot water heaters seem to run a LOT and make a loud fan noise when doing so. The running does not seem to coincide with use of hot water, either. By then our first gas bill arrives and it too is a doozy. We locate breaker for water heaters and turn it off when we leave and back on when we arrive. This continues and has helped gas bill but not the constant fan noise when on or warm water from cold taps.

I am told it could be as simple as a failed mixing valve anywhere (shower, kitchen sink, anywhere there is not a Hot and Cold tap) to (worst case) hot water and cold water plumbed wrong somewhere in the infrastructure. It is a large home, three stories and hot water heaters are side by side on first floor. There are four showers. Dishwasher, washing machine. Where would you start?

I intend to have a plumber out to address issue but had hoped to isolate further and provide more specific info by being here more. I have visions of multiple visits without progress. All I know by being here couple days a week for several months now is it is a real problem. Everyone reports showers start hot then turn cold and by end of shower you have to practically have all the way to HOT for warm water. I suspect this why there are two hot water heaters, I imagine renters would have complained about not enough hot water. When we are here, we often come without kids and use the master shower only, it still runs colder quickly regardless.

I am happy to post pictures, answer questions in effort to troubleshoot here before calling in plumber Thanks for any insight and direction you can provide.

 

[Smooky]

Some pictures might help, showing connections at and around hot water heaters, under sinks, at mixing valves. Do you have a recirculation pump on the hot water line somewhere? Is this a single family home or town house, apartment etc?

"Handyman hired comes out rules out leak between home and water line by turning off water to home and monitoring meter throughout day."....Do you mean he turned off all water using fixtures and then watched the meter to make sure there are no leaks under ground etc?

 

[Sponsor]

 

[Ladycfp]

I will post a photo mid week when I am back up there. There must be a recirculation pump, hot water gets to taps right away on second and third story. It is a single family home. Cold taps run cold-ish initially and very quickly get warm.

He turned off water at shut off valve to home and monitored meter to rule out underground leak. We turned it off at fixtures and toilets was next step and wh he replaced parts in several toilets that were leaking.

Thanks.

 

[Runs with Bison]

This sounds like a problem with the cartridges in a shower/bath. I've never had this problem before, but if the cartridge in the fixture isn't installed properly it will bypass and mix hot and cold water in other fixtures. Plumbers here talk about this as being a frequent problem.

 

[Toolaholic]

Excellent call !

 

[Jadnashua]

A cross-over somewhere is the likely cause of the warm 'cold' water tap, but that is still not a reason for high bills as with no water flow, there's no extra water to heat. What you want to do is leave the main water shutoff on, make sure nobody is using any water, THEN monitor the water meter. My guess is that you may have an internal (maybe under slab) leak. These can be nasty to find, and are often bypassed by running new pipes. If the meter DOES move while there's no intended water use, then shut off the supply to the WH and see if it stops. That would isolate it to the hot water side.

 

[Ladycfp]

Hot water heater- pictures

 

[Smooky]

I don’t see anything that jumps out at me but I have a few thoughts and questions. It is a little hard to see the pipes and fittings that are coming through the wall. Which way is the water going through the pump? There should be arrows. Is there a check valve of some sort in the cold line? Does the recirculation pump run all the time or is it temperature controlled or something? My guess is the recirculation pump is in a dedicated return line and it sends water back to the hot water heater through the tank drain. (Is this true?) There might not be a check valve or one that is not working in the cold line. If you run the cold or if it is leaking, then the water takes the path of least resistance. Since the hot water is being pushed through the hot water tanks it may be going into the cold line. If the cold water is running or leaking then there is less pressure in the cold line and the water in front of the recirculation pump is slightly higher pressure so it pushes into the cold line. You should be able to feel the lines and tell what is happening when the water is running. I would do this test with no water running, only the hot and then only the cold. The cold inlet should be the water line with the expansion tank. See if you can feel hot water backing into the cold inlet of the hot water heater when you are running the cold water at one of your sinks. (Is that happening?) Do you have a washing machine “Y” connect hose, connecting two faucets such as two outside hot and cold faucets or at a washing machine? I also see this problem with pre-rinse faucets in restaurant kitchens and at mop sinks that have hot and cold mixing faucets. Do you have any of these items? As mentioned above some shower valves can cause problems too.

https://www.acehardware.com/departments/plumbing/hoses-and-tubing/discharge-hoses/42093