RE: Tank not heating water during winter

[choc-holic]

Hey all,

Just wondering if anyone can help me out with this conundrum of mine.

I'm currently renting a unit in an apartment and I live on the highest floor (3rd floor). This is my second winter staying in it and once winter comes (as with last year) the hot water supply becomes unpredictable. Whenever it rains throughout the day or when the weather is really cold, the water heater tank somehow doesn't heat up the water. Only cold water flows out, sometimes luke warm. A lot of the time this continues for two consecutive days before hot water flow resumes.

During summer the hot water supply is fine. There may be the occasional one odd day where the hot water supply is cut but that doesn't bother me.

The agent has sent plumbers and electricians, all of which can't seem to find or think of any problem with it. The plumber has even changed the water heater tank (each unit in the apartment has its own tank). But the problem remained.

The water pressure in the unit I'm staying at is low (according to the plumber it's because the unit is on the highest floor). And no one else in the apartment seems to have the same problem. No long showers are taken, I don't even use hot water to wash the dishes or laundry (for fear that the hot water supply may 'run out').

Hopefully someone in this forum is able to suggest some possible solutions or may have an idea of what the problem may be. I would be eternally grateful. The only reason why I bear with this apartment is the trouble of moving out and its location.

Thank you in advance.

 

[johnjh2o]

It sounds like you have a cross connection between the hot and cold water lines. The most common is a single lever tub or shower faucet with a failed cartridge.

John

 

[DIYer]

i have same problem except i'm on first floor and the problem is not just in the shower. how do you explain no hot water in all areas, i.e., kitchen sink and bathroom sink which have knobs or hot and cold? how long should it normally take the water to get hot after having it left off for about 2 months? Temps outside 35-40 middle of night and 40-55 daytime. all of my pipes are in my crawspace also but the hot water tank is in my bathroom. when the water gets hot, does the hot water heater feel hot?

1) how long does it normally take water to get hot, in the hot water heater?
2) does the hot water tank feel hot when water is hot?

 

[johnjh2o]

The slowest water heaters are electric. Starting from a cold tank you should be getting hot water in less then 1-1/2 hrs.

John

 

[reedplumber]

Dumb question here but they aren't using hot water out of the tank for heat in the apartment I.e. radiant floor heating or baseboard heaters are they? Could be why you have no hit water in the winter but plenty in the summer

 

[Beni]

So your on the top floor and your pipes run in the attic space. Whats happening is when the attic is cold the hot water in the tank is thermal siphoning up the hot water pipe to the attic piping and cooling off. The cold water in the attic is then falling back down in the same pipe.

Sort of a one pipe steam system, but using hot water. All the hot water is going to heat the attic I'm thinking you have an electric heater as a gas heater would recover the loss better..

When its warm out and sunny the attic is hot and there is no thermo siphon.

The fix is easy. Have a plumber install a heat trap on the hot water line out of the tank. This is an S riser, that goes up oh 20", offset horizontal a few inches and drop back down 18 inches and then goes back up and connects to the existing hot water piping.

The S bend in the hot water line will prevent the hot water from thermal siphoning and will keep the hot water in the tank and you'll have hot water all the time, rain or shine. This would only happen at the top floor apartments as the lower floor piping is run in a ceiling with a heated space above.

Beni Bacon, PE, CIPE

 

[IFIXH20]

i have same problem except i'm on first floor and the problem is not just in the shower. how do you explain no hot water in all areas, i.e., kitchen sink and bathroom sink which have knobs or hot and cold? how long should it normally take the water to get hot after having it left off for about 2 months? Temps outside 35-40 middle of night and 40-55 daytime. all of my pipes are in my crawspace also but the hot water tank is in my bathroom. when the water gets hot, does the hot water heater feel hot?

1) how long does it normally take water to get hot, in the hot water heater?
2) does the hot water tank feel hot when water is hot?

If you still have that 10years old used water heater both of your heating elements may have gone bad now, more than likely you were working on one heating element for awhile.

 

[Beni]

1) how long does it normally take water to get hot, in the hot water heater?
2) does the hot water tank feel hot when water is hot?

1. About 2 hours for the typical 40 gallon residential electric heater. Its roughly an hour for each 20 gallons heated. About 45 minutes for the typical residential gas heater.

2. The tank shell if the insulation is good would not seem warm. But the hot water pipe out of it would be hot. Maybe too hot to touch, depending on thermostat setting..