My 18 year old 50-gallon hot water has 5 pipes connected to it:

Pipes 1-3 below come out of the cinderblock wall on the "cold"
(inlet) side of the hot water heater

1. 3/4" cold water supply pipe (input) with a shutoff valve

2. 1/2" pipe (adjacent to the supply line) that connects to the
Supply line between the supply line shutoff valve and the
Hot water heater inlet on the tank

3. 3/4" pipe from the P/T relief valve to the outside drain pipe

Pipes 4-5 below come out of the cinder block wall on the "hot"
(outlet) side of the hot water heater

4. 1/2" pipe from hot water heater outlet pipe

5. 1/2" pipe from P/T relief valve


Question 1: Cutting pipe 2 produced no water flow, and it is
downstream of the S/O valve so it apparently acts as some
kind of bypass??? for the supply cold water when the tank is full?

Question 2: after cutting pipe 5 I tried pouring water into it to see
if it was connected to the outside drain. This action quickly filled
the pipe and it did not drain...

My Heat Pump is adjacent to two capped copper pipes. I vaguely
recall "waste heat" from older heat pumps was used to assist in
Heating hot water, but this isn't done any longer.

Does pipe 5 have something to do with heat from the Heat pump?

Thanks for any thoughts!

Tom

Hey Taneal:

This is a hot water storage tank with a tankless coil at boiler or an immersed coil in it... yes?

What name is on the STORAGE TANK.. Any chance you could post a pic. Of all this..

Let us know... MARK

.

Mark,

Thanks for your response.

I'm referring to a Ruud 50 gallon capacity tank-type Residential Electric Water Heater that was manufactured in 1990.

I have disconnected and discarded this unit, so a photo would only show the cut pipes protruding from the wall.

The Instruction manual for this unit depicts only a *single* pipe connected to the T/P relief valve. This pipe leads to a drain.

In MY installation there were *TWO* pipes connected to the relief valve. One pipe leads outside the house to a drain as you
Would expect. The other pipe disappears into the cinder block wall. When I pour water into this pipe, the pipe fills with water
And does NOT drain out. I can't figure the purpose of this pipe or where it goes...

Tom

Quote:

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Originally Posted by taneal1953

My 18 year old 50-gallon hot water has 5 pipes connected to it:

Pipes 1-3 below come out of the cinderblock wall on the "cold"
(inlet) side of the hot water heater

1. 3/4" cold water supply pipe (input) with a shutoff valve

2. 1/2" pipe (adjacent to the supply line) that connects to the
Supply line between the supply line shutoff valve and the
Hot water heater inlet on the tank

3. 3/4" pipe from the P/T relief valve to the outside drain pipe

Pipes 4-5 below come out of the cinder block wall on the "hot"
(outlet) side of the hot water heater

4. 1/2" pipe from hot water heater outlet pipe

5. 1/2" pipe from P/T relief valve


Question 1: Cutting pipe 2 produced no water flow, and it is
downstream of the S/O valve so it apparently acts as some
kind of bypass??? for the supply cold water when the tank is full?

Question 2: after cutting pipe 5 I tried pouring water into it to see
if it was connected to the outside drain. This action quickly filled
the pipe and it did not drain...

My Heat Pump is adjacent to two capped copper pipes. I vaguely
recall "waste heat" from older heat pumps was used to assist in
Heating hot water, but this isn't done any longer.

Does pipe 5 have something to do with heat from the Heat pump

p?Thanks for any thoughts!

Tom

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Hey Tom,
There are heat pumps and AC to water heater heat exchangers. This is a small box on the wall with 4 copper pipes coming out of it. 2 go to the AC and the other 2 go back to the water heater. Is this the "heat pump" you're describing? You also say in #3 that the discharge line from the T & P valve is 3/4" but later on in #5 it morphs into a 1/2" line, Please explain?

Quote:

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Does pipe 5 have something to do with heat from the Heat pump

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Are you saying that the 1/2" line tees off from the T & P valve 3/4" discharge line? What's it connect back to? Can you give me a better explanation/ thanks, Tom

Hey Speedball, thanks for your response.

See NEXT message for a description of my Heat Pump.

In my original post the numbers 1-5 refer to INDIVIDUAL pipes. Pipe #3 and pipe #5 are BOTH connected DIRECTLY to the T/P relief valve mounted on the water heater itself. Pipe #3 is 3/4" and connects to an outside drain. Pipe #5 is a 1/2" pipe. I don't know the purpose of pipe $5 or where it goes. Pipe #2 is also unknown.

There are a pair of capped copper pipes that emerge from the outside wall adjacent to my heat pump. I think that some heat pumps route the "waste" hot air from the cooling cycle back to the hot water heater to assist the heating process. My guess is that pipe #5 is part of that system. I would think that this would require two pipes to form a loop which may explain the purpose of Pipe #2 which "tees" into pipe #1 between the hot water heater itself and the shutoff valve.

Could it be that the hot water heater was "set up" to use the waste heat from a heat pump, but the type pump that is currently installed doesn't have that capability? This would explain why the outside lines adjacent to the heat pump are capped off...

The above is purely speculation on my part.

Tom

The Heat Pump I'm referring to is located outside the house. It has a large fan built-in at the top of the unit. It's a fairly large unit, about 2.5' x 2.5' sides, and about 4' high. It heats or cools the house as required. Heating needs here in Florida are minimal, but it does a FINE job of cooling the house.

Tom

Gotcha Tom,
Your heat punp's a AC reverse air unit that sounds like you had a heat exchanger connected from the AC to the water heater. And you're correct, it doesn't take much heat to stay warm in Florida in the winter time, although I've seen it snow in Sarasota. Now, back to your mystery pipes.

Quote:

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Could it be that the hot water heater was "set up" to use the waste heat from a heat pump, but the type pump that is currently installed doesn't have that capability? This would explain why the outside lines adjacent to the heat pump are capped off...

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Ya almost nailed it. It sounds like you had a heat exchanger installed that has been removed and the lines capped off. I'm a little confused. Why would you wish to eliminate your 50 gallon water heater? What replaced it ? Did you move the water heater to a new location. I have a problem. Your explainations only seem to invite more questions. Tell me about the condensate drain line from your AC. PVC or copper? What size? Where does it terminate? Could the AC condensate line be the line connected to the hot water T & P valve 3/4" line?
In all the confusion what I think you are looking at are pipes that are no longer in use. I think at one time you had a heat exchanger that conducted the heat from the AC Freon to the cold water of your old water tank and now it's all been removed. There's no doubt in my mind that the 1/2" line that ties to the T & P valovw discharge is a condensate drain of some sort. Is this heat pump a original unit or is it a replacement? Why did you eliminate the 50 gallon water heater and if you've replaced it where's your water heater now?? Regards, Tom

I removed and discarded my 18 year old tank-type hot water heater when it developed a leak. My plan is to replace it with a tankless water heater which will be installed in the same location. So, of course I needed to be certain which pipes were necessary and which were not prior to installation.

While pondering my dilemma I just now discovered that one of the (outdoor) capped pipes was loose enough to wiggle. Sure enough, wiggling this pipe from outside made pipe #2 move around inside the house. So, I cut off the cap on the outside end of the pipe and poured water into the pipe inside the house. The water flowed freely out the formerly capped end. That identifies pipe #2 as unnecessary.

Repeating the procedure with pipe #5 proved that it was the other capped pipe leading outside near my heat pump. It is also unnecessary. It appears that this water heater was "set up" to receive waste heat from the outdoor heat pump via a heat exchanger, but was not actually connected to the heat pump itself.
Why pipe #5 was connected to the relief valve is beyond my comprehension. If it had been connected *between* the relief valve and the tank I suppose it would have allowed hot water from the heat exchanger to flow into the water heater's tank, but it definitely was not connected that way.

Pipe #1 is the cold water supply line, pipe #3 is the T/P drain pipe, and pipe #4 is the hot water outlet, so I'm ready to connect my tankless water heater, and I'll just cap off pipes 2 & 5.

To all who replied; THANKS for your help!

Tom

Glad we could be of service. You had a interesting problem and it was fun trying to figure it out without being there to see. Regards, Tom