Hot Water Tank Issue?

[flamesrule_kipper34]

Hey guys,

My tenant mentioned today that thehotwater tank was stuck turning on and off. He sent me a video and basically you could hear it turning itself on and off every 5 or so seconds. He cycled the power off and then on manually and the issue went away.

Am a bit worried this may become an issue but thought I'd ask if anyone knows what could cause this, don't want to them to lose hot water suddenly. It's 5-6 years old so not very old.

[YSF Regina]

We have a 5 year old Rheem high efficiency tank that acts up when it gets super cold. It was explained to me that the air intake from outside can become restricted with frost and causes the unit to attempt to fire up, shuts down, fires up, shuts down and so on.

[llwhiteoutll]

Have them go outside and check the intake or exhaust for ice. There might also be a small metal screen that is getting clogged with ice, the screen can be removed and it should solve the issue

[Fozzie_DeBear]

If not the exhaust...the thermocouple might be fried

[zarrell]

Mine does this when it's cold out. The grill on the intake gets frosted over and the tank will time out if it can't get enough air flow.

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[flamesrule_kipper34]

Thanks guys I'll ask the tenant to look into those things much appreciated!

[GP_Matt]

We had the same thing over the holidays with lots of guests and the cold weather. It was definitely the air intake but we couldn't see any clogs so we removed the air intake pipe from the hot water tank and just pulled air from the house. Once it warms up we will reconnect the air intake.

As far as I can tell the only drawback is that the house becomes less efficient with negative pressure pulling cold air into the house.

[Fuzz]

If you have a well sealed new house that is a big risk. It will suck air from anywhere for combustion, including the hw heater exhaust, and furnace exhaust. If you turn on a kitchen fan and bathroom fan(several hundred cubic feet per minute of air-think about that for a sec...), you have all these things evacuating air from your house, and the only holes in being the exhaust ones. That is how you get carbon monixide in your house.

I hope you have a functioning CO detector, and if you insist on carrying on, at least open a window near the HW heater that isn't near water pipes, so they won't freeze too....

[stampsx2]

Originally Posted by GP_Matt

We had the same thing over the holidays with lots of guests and the cold weather. It was definitely the air intake but we couldn't see any clogs so we removed the air intake pipe from the hot water tank and just pulled air from the house. Once it warms up we will reconnect the air intake.

As far as I can tell the only drawback is that the house becomes less efficient with negative pressure pulling cold air into the house.

I did the same thing. Disconnected the air intake in the basement and all of a sudden the hot water tank starts working. Not sure how unsafe the this is though.

I’ve cleaned out the air intake multiple times but a day or so later had the same problem every time.

Could keep cleaning the intake pipe but would love to know what’s actually happening in there to get a more permanent solution.

[speede5]

Originally Posted by Fuzz

If you have a well sealed new house that is a big risk. It will suck air from anywhere for combustion, including the hw heater exhaust, and furnace exhaust. If you turn on a kitchen fan and bathroom fan(several hundred cubic feet per minute of air-think about that for a sec...), you have all these things evacuating air from your house, and the only holes in being the exhaust ones. That is how you get carbon monixide in your house.

I hope you have a functioning CO detector, and if you insist on carrying on, at least open a window near the HW heater that isn't near water pipes, so they won't freeze too....

This shouldn't be a problem in a newer house as they are required to have a combustion air inlet in the furnace room for conventional appliances. Hi efficient have their own inlets and do not draw from the surrounding air. The inlet and exhaust are sealed from the ambient air.

Older houses never had the inlet and this was a problem but anything built or serviced in the last ~20 years should have some combustion air supply.

[speede5]

Originally Posted by stampsx2

I did the same thing. Disconnected the air intake in the basement and all of a sudden the hot water tank starts working. Not sure how unsafe the this is though.

I’ve cleaned out the air intake multiple times but a day or so later had the same problem every time.

Could keep cleaning the intake pipe but would love to know what’s actually happening in there to get a more permanent solution.

Very common problem with the air intake. Your solution may get you through the night but it's not a great idea. There are inlet/exhaust combos that keep ice and snow from accumulating on the inlet. You can also move the inlet and exhaust farther apart, cause the exhaust has humidity and gets drawn into the inlet, where the moisture freezes and builds up on the cold inlet.

Really you just have to monitor your inlet, mine clogs up 3 times a day in the right conditions. I have to modify it a bit but never seem to have the time and I forget in summer when theres no issue

[White Out 403]

my hot water stopped this morning too, and this happened before so i knew what to do. i have a newer home and the exhaust can freeze over. i cleared it out and reset my hot water tank, and boom, hot water.

[Fuzz]

Originally Posted by speede5

This shouldn't be a problem in a newer house as they are required to have a combustion air inlet in the furnace room for conventional appliances. Hi efficient have their own inlets and do not draw from the surrounding air. The inlet and exhaust are sealed from the ambient air.

Older houses never had the inlet and this was a problem but anything built or serviced in the last ~20 years should have some combustion air supply.

I had a new high efficiency furnace put in about 10 years ago, and they did run a fresh air supply, but it is on a damper that only opens when the furnace is on. I thought most of the good setups ran this way, otherwise you are just dumping cold air in the house all the time.

[Ducay]

Originally Posted by Fuzz

I had a new high efficiency furnace put in about 10 years ago, and they did run a fresh air supply, but it is on a damper that only opens when the furnace is on. I thought most of the good setups ran this way, otherwise you are just dumping cold air in the house all the time.

To be fair, the cold air doesn't really dump in unless the nice warm air is being asked to leave (exhaust fan, combustion), so it isn't as bad as you'd think.

Plus with older homes (ie not that long ago, say 10 years), you'd have both the combustion air and the fresh/make-up air lines open all the time. So I'd argue most homes are still like this. Only with the advent of the fancy pants units that pre-warm the make-up air and the controlled dampers on combustion air do you not have a source of chilly air open all the time.

High eff units are even more skookum as they draw and exhaust without ever dealing with the air in your house.

[speede5]

Originally Posted by Fuzz

I had a new high efficiency furnace put in about 10 years ago, and they did run a fresh air supply, but it is on a damper that only opens when the furnace is on. I thought most of the good setups ran this way, otherwise you are just dumping cold air in the house all the time.

That would be a mid efficient. High efficient have an intake and exhaust made of 2" PVC, or ABS if it's a bit older. Like Ducay said, the air in your house is not a factor.

Yes the fresh air supply may have some sort of damper but it's going into a furnace room which is typically quite warm and doesn't effect the house temperature much.

[Fuzz]

No, it's high efficiency. It's got the 2 PVC pipes, Energuide rating of 96.7. The fresh air duct gets dumped into the cold air return via the damper, so I guess it isn't for combustion air. Now I'm not sure why they put it in....

[speede5]

Originally Posted by Fuzz

No, it's high efficiency. It's got the 2 PVC pipes, Energuide rating of 96.7. The fresh air duct gets dumped into the cold air return via the damper, so I guess it isn't for combustion air. Now I'm not sure why they put it in....

Is it just a duct allowing outside air in or is it part of an air exchanger? New houses are so air tight they need air exchangers to get rid of humidity. The inlet air is sometimes routed into the furnace return.

[Fuzz]

Just outside air in, no exchanger. It's a 65 year old house.

[Sainters7]

We had the same problem over here around that exact same time, it was from the extreme cold outside at the time (or so I was told...I'm no expert)

[stampsx2]

Originally Posted by speede5

Very common problem with the air intake. Your solution may get you through the night but it's not a great idea. There are inlet/exhaust combos that keep ice and snow from accumulating on the inlet. You can also move the inlet and exhaust farther apart, cause the exhaust has humidity and gets drawn into the inlet, where the moisture freezes and builds up on the cold inlet.

Really you just have to monitor your inlet, mine clogs up 3 times a day in the right conditions. I have to modify it a bit but never seem to have the time and I forget in summer when theres no issue

I’m starting to think this no hot water problem has nothing to do with frost buildup in the intake. I’ve cleaned it out numerous times and almost no frost falls out during cleaning. Soon as the temperature warms up above -25, all of a sudden everything starts working??

Could it be the thermostat or some sort of part that can’t function at those really cold temperatures?