Questions about replacing circ pump

1962_split

Hey everyone, I have some questions about the circ pump on my boiler system.  My house was built in 1962 and has a 3 zone boiler that was replaced in 2010.  I recently had an issue where the top level rads had no heat.  Called a local mechanical company who bled the rads and advised the circ pump was faulty due the its temp which was 168 degrees. He said he would locate a pump and provide a quote to replace.   Half an hour after he left the rads started working again and advised him of this.  The next day he called with a quote to change the pump and asserted it needed to be changed despite the fact the rads were functioning as they should.   The pump was changed and I’ve since checked the temperature of the pump which reaches 170 degrees at times.  

My question is, does a faulty pump in fact cause an increase in operating temperature?  Is a temperature reading a reliable tool to diagnose a faulty pump if the reading fluctuates within the heat cycle of the boiler?   

EBEBRATT-Ed

First of all please delete you pricing. Pricing is not allowed on this forum.

It's hard to say but if you got heat after the system was bled (with the old pump) yet he went ahead with the replacement.

Sounds like we both know the answer to this question.

A temperature reading on the pump body will vary with the water temperature in the boiler and also depend on weather the pump is mounted on the supply or return pipe.

Normal temp could be as high as 200 on the supply and probably 180 on the return.

It's problem in this day and age with fewer quality technicians. Homeowner put their trust in the tech to only replace parts that are defective.

Maybe he saw something wrong with your old pump? Leaking? How old was it?

Can't comment on the price.

1962_split

Thank you for the reply and have revised the price in the post.  

I can’t say for certain the age of the pump but I would imagine it was changed when the system was replaced so ~12 years.  

There were no leaks or noise coming from the old pump.  Pressure in the system is 30psi.  

I’ve added a photo of the system. 

1962_split

neilc

uh,
the 30 psi, and water on the floor are a bigger problem right now,
where's the expansion tank ?

1962_split

Floor is dry that is the shadow from the pipes above.  There are two expansion tanks. 

How do I lower the pressure?

EBEBRATT-Ed

@1962_split

30 psi sounds high. Most systems run 15 psi. How many floors are you heating? 15 psi is enough to do 2 floors. Please check the boilers relief valve to see the psi it is set at. Something seems off.

I also do not see an expansion tank or a PRV (pressure reducing valve) for water make up

1962_split

My home is a 4 level split and 1740sqft.  Pressure relief valve is set at 30psi.  

Here are the expansion tanks:

Could this be the prv? 

neilc

lowering pressure to ~25 while it's that hot is as easy as finding a working drain on the system, and a bucket or a hose, it shouldn't take too much water to do it,
caution, 180 is HOT, be careful,

but why +30?
you need to check the expansion tanks, or if the water feed is leaking by,
does the boiler also heat the domestic water?

1962_split

I have a hot water tank so I don’t think it does.  

Thanks for the comments everyone, I’m learning lots.  

EBEBRATT-Ed

@1962_split

No that's a saddle tap valve not a PRV. On the left side of your boiler is a small 1/2" copper pipe. That's probably the water feed trace it to find prv.

30 psi is too high. It's possible you just have a bad pressure gauge they do go bad. If you have a drain valve on the boiler where you attach a garden hose you can buy a pressure gauge 0-30 psi and attache it to the drain and open the valve to check the pressure versus the boiler gauge

1962_split

Is this the pipe you’re referring to? 

  My sense is that the 30psi reading is accurate as it was 12psi before the work was done to the system but I will double check with a different gauge.  Is this also the valve I can use to drain some of the water?

neilc

yes, you can drain water and pressure from there,
No, no reducing valve there,
you might have a manual feed coming diagonal across the left top of the boiler in a prior picture,

could you post a more distant picture or 2 showing floor to ceiling, and of the pipes around the boiler

1962_split

I think this is the feed valve.  

WMno57

The gauge shows 14psi. It is a dual marked gauge. The inner scale is psi, and the outer scale is feet. The photo in post 8 shows 14psi.

neilc

ok,
that 1/2 inch copper coming into the return 90 at the boiler,
follow that back to the wall, and up to the ceiling,
that green device up there is your pressure reducing feed valve,
there should be a manual valve there on that line also if the reducer is leaking by,, or to service or change that reducer valve.

neilc

and I was wrong about the diagonal,
that's a bypass between your feed and return

1962_split

So pressure is at 14psi (good catch WMno57).

Is measuring pump temp the best way to diagnose a worn (but still functioning) circ pump?  I just took a measurement and it’s 168.5.  

EBEBRATT-Ed

@1962_split

The pump body will be the same temperature as the water going through it. If the motor overheats it could trip out on overload. Rarely happens with a circulator.

I don't know anyone that diagnoses a pump by measuring temperature unless it's a motor issue which I doubt