gate valve vs ball valve - hot water pump

[mjz]

I have two gate valves which isolate my hot water circulation pump (B&G series 100). They are starting to leak (very slow drip - drip) and I am thinking I should replace them. Would I be better off to use brass ball valves or just replace the existing gate valves (not sure of the metal)?

https://www.dropbox.com/s/v5f0m68gobvnr5t/20161130_132403.jpg?dl=0
(you should be able to zoom in on this large image once loaded)

It looks like I'll have to un-bolt the bottom of the pump so I can unscrew the valves and pipe back to the water heater.

 

[Mr_David]

Use a quality ball valve. If it's a cheap import the stems break.

install valve at heater and drain between valve and pump

 

[mjz]

Use a quality ball valve. If it's a cheap import the stems break.

install valve at heater and drain between valve and pump

Use two ball valves for above the pump as well as below - correct? (as well as swap the hose bib in front of the lower valve.

I'm waiting to receive flange gaskets before I dismantle the setup.


(just irks me that the original plumber didn't "know" or wasn't thinking when he first installed the loop system.)

 

[frodo]

......................

 

[Mr_David]

I'm waiting to receive flange gaskets before I dismantle the setup.

Good foresight.

 

[mjz]

Good foresight.

Well - no luck so far. I took out the pump and there was quite a bit of rust in the pump body (where the pump impeller sits and turns) at the inlet. It looked like it could be causing a restriction. I cleaned it out creating a good passage again. I flushed the return line (pipe going into the pump) and it flowed great (full pressure/flow). There is clearly no restriction in the loop.

So I reconnected everything and flushed the pump body to remove air before tightening down the bolts and restored power.

Ran the pump for an hour - no change (usually it takes 5 minutes for the return line to heat up). Pipe still cold to the touch. Damn ....

I was hoping to avoid re-plumbing the line to put the hose-bib valve swapped with the shutoff valve and drain the hot water tank in the process - i.e. I was looking for an easy fix.

Maybe the old impeller is worn somehow ... (not obvious to the eye) and not moving the water sufficiently. I can't believe there is an airlock in there ...

sign me 'frustrated'. What a puzzle.

 

[frodo]

which way is the arrow on your pump pointed ?

away from the w-heater or towards the w-heater

which way is the arrow on the check valve pointed ?


can not see the arrow in the picture, but it looks like the pump is pumping away from the heater
it should be pumping to the water heater.

if you have a check valve,,need to loook at it, if it is pointing toward the heater and the pump is pumping into a check valve woop dey it is


did you verify water flow when the pump was removed ?

 

[mjz]

which way is the arrow on your pump pointed ?

away from the w-heater or towards the w-heater

which way is the arrow on the check valve pointed ?


can not see the arrow in the picture, but it looks like the pump is pumping away from the heater
it should be pumping to the water heater.

if you have a check valve,,need to loook at it, if it is pointing toward the heater and the pump is pumping into a check valve woop dey it is


did you verify water flow when the pump was removed ?

The arrow on the body is pointing towards the water heater. There is no check valve. The pump used to work just fine - only in the last few weeks did I notice that the water took forever to get hot whereas before it was near instant (purpose of the pump in the first place). Touching the pipe near the water heater would always get hot - no longer. And I would hear pipe "sounds" as the copper pipes expanded from the heat up. That no longer happens. There is some circulation because if I let the pump run for 4 hours the pipe will warm (never hot) and warm water will come out of the tap and then get hot. But 4 hours running when 5 minutes use to do it is not practical. I may just need a new pump (keep the motor, but replace the pump housing).

very strange ...

 

[frodo]

The arrow on the body is pointing towards the water heater. There is no check valve. The pump used to work just fine - only in the last few weeks did I notice that the water took forever to get hot whereas before it was near instant (purpose of the pump in the first place). Touching the pipe near the water heater would always get hot - no longer. And I would hear pipe "sounds" as the copper pipes expanded from the heat up. That no longer happens. There is some circulation because if I let the pump run for 4 hours the pipe will warm (never hot) and warm water will come out of the tap and then get hot. But 4 hours running when 5 minutes use to do it is not practical. I may just need a new pump (keep the motor, but replace the pump housing).

very strange ...

what is controling the pump ?
is that a strap on aqua stat I see ?

remove the aqua state clean the pipe with sand paper,
clean the sensor and see if that helps.

If you do not have a ck valve,,,do you xperience warm water on the cold side of your faucets ?

 

[mjz]

what is controling the pump ?
is that a strap on aqua stat I see ?

remove the aqua state clean the pipe with sand paper,
clean the sensor and see if that helps.

If you do not have a ck valve,,,do you xperience warm water on the cold side of your faucets ?

The cold water / hot water system are completely isolated from each other.
The hot water system has a copper pipe loop which takes water from one end of the hot water system and pumps it back to the hot water tank. The aquastat is not the issue. The pump runs.

I am beginning to think that rust may have accumulated at the bottom of the loop (see picture) where the return line leaves the pump, makes a 90 degree turn and then flows into the hot water tank. Rust may have accumulated there restricting flow. I won't know until I open it up (which I was trying to avoid). Perhaps the impeller has some rust bits in it that I did not see (didn't really look) which is affecting flow.

 

[pasadena_commut]

I am beginning to think that rust may have accumulated at the bottom of the loop (see picture) where the return line leaves the pump, makes a 90 degree turn and then flows into the hot water tank. Rust may have accumulated there restricting flow. I won't know until I open it up (which I was trying to avoid). Perhaps the impeller has some rust bits in it that I did not see (didn't really look) which is affecting flow.

Does the check valve in the drawing restrict flow to be only into the tank? If not you may be able to clear the blockage by temporarily removing the faucet, or partially disassembling it, at the bottom and running water "backwards" through the tank and out the pipe. Once the faucet is off the pipe poke around with a bit of wire while the water is running and it should clear out, assuming it is loose rust. If there is a gate valve in the line somewhere the rate can be controlled and it isn't an instant flood. If all you have is a ball valve, well, that could be really messy.

We have nearly 70 year old galvanized pipes in our house and doing anything to the plumbing tends to release rust which jams the next faucet or valve downstream unless it has been preemptively opened. One of these events jammed the hot water line from the water heater to the washing machine, maybe 40 feet away. With the faucet fully open on the washing machine end only a tiny trickle would come out. This is how it was cleared: shut off water to house, detach the hot water outlet at the heater, attach a hose to that pipe and run it to the bathtub, detach the cold water hose from the washing machine and screw it onto the hot water faucet, open the cold water faucet fully, slowly turn the house water back on. Driving everything in reverse cleaned out that long pipe. Many years later and it has not jammed like that again. The point I'm trying to make is that sometimes when rust moves around it packs up "directionally", so that making the water flow in the other direction can flush a line that just won't clear when run in its usual direction.

We had to cut a small section of pipe out last year to replace a gate valve which failed closed. Many of you know the drill, close the shut off, do some work, open the valve again, and stays shut even though the handle says it is open. The pipe was a little rusty inside but it was in remarkably good shape, given its age.