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How do I get air out of my hot water recirculating pump?

How do I get air out of my hot water recirculating pump after my water heater was changed? It makes a fluttering sound? Thanks.

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There is a bleed screw located on top of the impeller housing, sometimes covered by a pry up plastic button.

Posted on Sep 13, 2009


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Heat not hot enough

Make sure blend door is opening all the way.When you have selection on hot,the door should be open to the heater core and the air recirculation should be open.Have it blow out in vents.

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Excess Hit Water Bill from Solar/electric Hot Water System

Cost calculations for recirculation system vary widely.
These systems cost more, and they cause higher operation cost of water heater.

1) When pump is OFF, then hot water is no longer leaving the tank.
Most recirculation systems have choice of timer for setting specific times of operation, or thermostatic operation that activates pump when sensor detects temperature less than 90 degrees

2) Condition of plumbing is suspect here because you are not receiving fully 90 degree hot water from the recirculation system.?.

Bad single-handle faucet cartridge, or bad recirculation check valve, are causes of crossover. Clean recirculation check valve with white vinegar. Replace worn faucet cartridge.
Test for crossover.

3) There are other suspects, such as water leak.
Drips, broken pipe, bad TP valve.
Turn off all taps and put ear against pipe to listen for running water.

4) High costs: Lifting single-handle faucet in middle will immediately cause cold water to enter tank. Even if no hot arrives at tap, because the cartridge is drawing both hot and cold in equal amounts when handle is lifted in middle.
Today it is more efficient to install dual-handle faucets so tank is not receiving constant dose of cold water when single-handle faucet is not used correctly or tediously.

Oct 29, 2012 | Water Heaters

1 Answer

I have an instant hotwater system with the futher most bathroom about 45' away. I am looking at adding a recirculating pump on a timer at the furthermost bathroom to get hotwater quickly in the...

Maybe I am not understanding your problem exactly, but if you have the instant hotwater system installed it should be measuring the temperature of the water in the hot water line and if it drops below the set level it should open the hot water side until the temperature is reached. If it was installed correctly it puts the hot water back into the cold water line so it isn't wasted.

Sep 18, 2011 | Grundfos RCP-96 Recirculation Pump for...

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The circulation pump making noise.

Question posted under Grundfos recirculation system.
If pump is making noise, then air or sediment is probably trapped at the impeller.
Remove pump, and connection between hot-and-cold pipes and clean with white vinegar.
Or use CLR but do not soak parts in CLR or it can cause damage.
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For a price, expert works with you while you work on water heater or any do-it-yourself project.
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Sep 06, 2011 | Grundfos Comfort System Recirculator ...

1 Answer

I have a Amrstrong Astro 25B050S recirculating pump on my 50 gallon State water heater (both installed in 2006). The timer works fine and the I can hear the Astro pump and the pump feels very hot to the...

If the pump is very hot, unplug it.
Heat damages motor coil and indicates that pump is not rotating at correct speed, or not rotating.
Take apart and clean inside pipe with white vinegar or CLR to see if pump rotor can be freed to rotate.
If pump does not rotate after cleaning, then replace pump.

Aug 16, 2011 | Astro Systems Armstrong Astro 20B050S-TA...

1 Answer

After installing the thermo bypass valve on the furthest sink faucet from the water heater, the sink faucet has no pressure, and there is hot water slowly comling out of the cold water valve.

It sounds like the installation loosened sediment inside pipe.
Remove sink aerator and see if you can flush open the faucet.

Also check if other faucets are receiving hot water from hot-and-cold taps that says if grundfos is pumping hot water from the water heater correctly.

When recirculation pump is running, both hot and cold water lines have hot water.
If other faucets have hot water in both lines, then that tells you the blockage is localized in furthest faucet supply lines.
You may have to dissemble those supply lines and flush the sediment out.

Dec 30, 2010 | Grundfos Comfort System Recirculator ...

1 Answer

I have a laing cirulating pump thats is worhing but now making noise so i took it apart see nothing but it was hot when running so is there any thing i can do to fix before it burns out

Open following link for Re-circulation information and resources:

If the unit is getting hot, it may have already slowed and is now spiraling to it end.
Try bleeding air out of water lines, and clean autocirc with CLR calcium lime and rust remover.
Recirculation systems have a built in check valve so cold water side of faucet will work correctly. If this check valve is stuck open or closed, it can affect a lot of things in the plumbing system.
For example, stuck check valve can cause tankless water heater not to operate. It can also cause autocirc pump to overheat.
Lines, or elbows clogged with sediment can also cause same problems with recirculation system. If your system has direct return line to water heater that connects into the water heater drain port, then clog in line can cause overheated pump. Check water flow, check water lines, and clean out autocirc.

Upvote the help.
And take advantage of fixya expert assistance live.
For a price, expert works with you while you work on autocirc or any do-it-yourself project.
Fixya is always less expensive than a service call.

Oct 22, 2010 | Laing Thermotech Autocirc Undersink...

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Grundfos recirculating retro fit hot water out of the cold side

they have it installed wrong it is pulling from the wrong side, it is supposed to pull ot water up to the fixture but then if it stays hot on the cold side they are backwards

May 27, 2009 | Grundfos RCP-96 Recirculation Pump for...

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