Power vent Hot water Heater clicking noises

[MIDan]

Hello,
Here is my situation my water heater is an American Water Heater Company, the energy guide label says it is model PVG[1,6,9,12]250T60N(IMG 1,2). So I searched their site and can't find that model. I was guessing the numbers in the brackets were a "could be this or this" situation, so I searched for PVG6250T60N but still the closest I can find is a PVG6250T62NV.
The problem I am having with this unit is that my wife and I moved into this house about 6 months ago and have had no problems with the unit, I was in our basement yesterday checking on something else and noticed the exhaust pipe from the hot water tank was disconnected right before it went through the wall. I reconnected the pipe so the exhaust was not venting into the house but a few hours later we heard a weird clicking noise. I went downstairs and realizes it was the hot water heater. The sound was coming from the control panel of the heater(IMG 3). It sounded like a rely quickly clicking or a valve quickly opening and closing.
The air intake is not vented to the outside it is a snorkel, I think that's what its called (PIC 4) the noise continued until I covered the underside of the snorkel. My theory is that the blower was sucking air in from the outside through the bottom of the snorkel only but it should be sucking air through the top/through the burner and so a pressure valve was flapping. Does this sound right to people or do I have a bigger problem on my hands?

 

[Bannerman]

Is the burner continuing to fire to produce hot water?

As it is a power vent unit, the fan needs to be running and flowing an adequate amount of air before the burner will fire. Because this issue started after reconnecting the exhaust vent, look for any obstruction in the vent leading through the wall to the exterior preventing the unit from exhausting, resulting in excessive pressure from the fan onward which will prevent the unit from firing.

I'm surprised the exhaust pipe was not glued, but apparently it wasn't. Something caused it to become disconnected which could be a result of too much pressure due to a restriction.

 

[Sponsor]

 

[Reach4]

The air intake is not vented to the outside it is a snorkel,

New to me. I guess the snorkel is in case the basement floods.

 

[MIDan]

New to me. I guess the snorkel is in case the basement floods.

Is the burner continuing to fire to produce hot water?

As it is a power vent unit, the fan needs to be running and flowing an adequate amount of air before the burner will fire. Because this issue started after reconnecting the exhaust vent, look for any obstruction in the vent leading through the wall to the exterior preventing the unit from exhausting, resulting in excessive pressure from the fan onward which will prevent the unit from firing.

I'm surprised the exhaust pipe was not glued, but apparently it wasn't. Something caused it to become disconnected which could be a result of too much pressure due to a restriction.

Is the burner continuing to fire to produce hot water?

As it is a power vent unit, the fan needs to be running and flowing an adequate amount of air before the burner will fire. Because this issue started after reconnecting the exhaust vent, look for any obstruction in the vent leading through the wall to the exterior preventing the unit from exhausting, resulting in excessive pressure from the fan onward which will prevent the unit from firing.

I'm surprised the exhaust pipe was not glued, but apparently it wasn't. Something caused it to become disconnected which could be a result of too much pressure due to a restriction.

I'm curious if the exhaust is too small it is reduced to about a 2in pipe before it goes through the wall but I swear I saw somewhere it needed to be at least 3 inches. Anyway the exhaust pipe is clear. I was completely wrong about my idea of what was going on though. The part connected to the blower is also connected to the intake, so air is drawn in from the top for the intake and the blower motor sucks in air from the bottom as far as I can tell. My dumb A** thought it would be a great idea to block off the airflow at the bottom luckily the motor didn't melt but it was hot. So now I'm lost again. The blower runs and it sounds like a pinball bumper is being hit repeatedly if I block some of the air coming into the top the noise stops. I agree about it not being glued, every user manual I have read says all joints need to be glued except the one at the blower. Any other ideas?
The white vent part has a number on it 4710867, but I haven't had much luck finding it.

 

[Bannerman]

The blower will be drawing the products of combustion up through the flue vent which runs through the centre of the WH. The snorkle down the side of the tank appears to deliver combustion air near to or into the combustion chamber below the storage tank, so a second blower wheel maybe pushing air down the snorkel.

I'm confused by your statement that you blocked off air into the bottom. Perhaps you somehow blocked the snorkel so a flap within intake duct which is no longer opening due to the blockage you introduced, but your initial posting indicated only clicking from the gas valve.

You didn't clarify if the burner is actually firing. As the WH incorporates a storage tank, hot water will continue to be available for some time after the burner is not firing, but you will likely hear the burner running when additional heat is being produced such as after you raise the water temperature setting.

A pressure switch(s) will sense the pressure increase caused when the exhaust fan is operating properly before allowing the gas valve to open to allow the burner to fire. If the pressure increase is too high, such as when there is a blockage or restriction in the exhaust vent to the outdoors, that will also prevent the gas valve from operating. If the water temperature at the height of the gas valve is cool enough to call for additional heat, the clicking you are hearing maybe the unit resetting after the air flow pressure switch is not allowing the gas valve to open

The exhaust vent pipe connected to the output of the exhaust fan appears to be 3" so it should not be reduced to 2" through the wall. That WH is not a high efficiency type so the exhaust heat content remains high enough that sufficient air must be added to dilute the hot gases so as to not overheat the PVC exhaust piping.

To determine if the gas valve clicking stops and if the unit will fire, remove any blockage you installed and also remove the exhaust pipe connection to return it to the same condition as you found it yesterday. If the clicking stops and the burner fires-up when the the water temperature setting is raised, then you will know the problem is caused by the restriction through the wall. Disconnecting the exhaust pipe is to be a temporary test only as the unit should not be permitted to operate with products of combustion venting into the home.

Suggest also installing a carbon monoxide detector nearby to your heating equipment as CO gas has no odor but is deadly.

 

[Master Plumber Mark]

WE had issues with that brand of gas thermostat way back then ....
they were defective new out of the box and were clicking like you are describing
something to do with the magnet within the control clicking .... brand new in the basement too....

I still have one of those replacement thermostats new in the box sitting on the shelf that they sent me but
I opted to just change out the heater instead to another brand to make the customer happy.
This was probably way back in 2005...


I am pretty sure that unit is at least 13 years old and I suggest that you dont waste any money on it
and just go get yourself a new Rheem power vent and forget about it

On another note that brand is junk and always has been so dont throw any
money at it.....