Sometimes You Win, Sometimes You Lose

Alan (California Radiant) Forbes

I remember a long time ago, Ellen Rohr gave a seminar on how to run your business at one of the Wethead or Wetstock gatherings. It may have been in Chicago. She asked the audience if anyone considered themselves a failure and I stood up. I looked around and I was the only one. I had never failed in business, but I remembered my job failures more than my successes because failures hurt more.

Today was one of those failures. One of my long time customers with a big house in a tony neighborhood wanted me to figure out why the heating wasn't working properly. They have copper tubing in ceiling plaster; 6 zones. Some of the thermostats weren't working and some of the zones only heated 1/2 the ceiling as shown on my infrared camera.

The boiler was an A.O. Smith Burkay with the pump on the return, pumping towards the x-tank and I thought, no problem. Switch the pump to the supply side, pumping away from the x-tank and purge the system and add wireless thermostats for any that weren't working. We switched the pump location and purged the zones; hardly any air came out and the heating quality hasn't changed.

I think that some of the loops in the ceiling were cut off in previous remodels. I had such optimism to begin with, but again, I'm the lone guy standing up.

DanHolohan

I have always loved your honesty, Alan. Thanks. 

GroundUp

Sometimes we just have to admit defeat. In this case, maybe trying to purge the zones individually would have eliminated the uncertainty if it were impossible to get flow through them. Radiant can be tricky sometimes, if loops have different pressure drops. I've run across this more than once and sometimes it takes some repiping to be able to isolate certain loops, but at least then the culprit is known.

Intplm.

@Alan (California Radiant) Forbes I like your style.
I too have been there but on a typical hydronic Finn tube system. Went in confident and ready to fix all.
Come to find out, the no heat was because a zone was capped in a wall years ago. Why? Who knows.
Me...egg on face...move on.

hot_rod

you went in and tried, not many would even take on a job like that, these days. I hope the owners appreciate you as much as we do🫶

EBEBRATT-Ed

Everyone of us that work in the field professionally has run into some situation like that.

Usually because some knucklehead did something that no professional would even consider doing.

Don't feel bad you tried.

HVACNUT

It doesn't sound like failure. It sounds like sabotage. How come no one blames Gremlins anymore?

GroundUp

So did you try to purge each loop individually or not?

EdTheHeaterMan

HVACNUT said:

It doesn't sound like failure. It sounds like sabotage. How come no one blames Gremlins anymore?

I always blame the gremlins or say the house is haunted 👻. It’s never my fault. LOL

Alan (California Radiant) Forbes

So did you try to purge each loop individually or not?

Yes, purging all the zones at once is a waste of time, as you know. We spent about an hour and a half doing it. We stuck the end of the hose in a bucket and let it fill and look for bubbles; usually very satisfying, but we didn't see one bubble - nada.

GroundUp

Alan (California Radiant) Forbes said:

So did you try to purge each loop individually or not?

Yes, purging all the zones at once is a waste of time, as you know. We spent about an hour and a half doing it. We stuck the end of the hose in a bucket and let it fill and look for bubbles; usually very satisfying, but we didn't see one bubble - nada.

Well if you had flow, the loop obviously isn't capped.... That's what I was confused about. A capped loop would have given you nothing in the bucket.

Alan (California Radiant) Forbes

Very observant, Groundup. 

For most of the zones, this can be accountable by the fact that there’s partial heating going on. Half the boy’s bedroom shows heat, a quarter of the massive living room gets warm. 

What doesn’t make sense and what you allude to is the fact that the dining room/entry zone shows nothing, but there’s plenty of flow when purging. 

I’m going to ohm out the old 26-99 pump when I go back today. Any other ideas?

EBEBRATT-Ed

amp draw on the circ to see if it is moving water

Alan (California Radiant) Forbes

EBEBRATT-Ed said:

amp draw on the circ to see if it is moving water

Yes, thanks. I meant amp draw.

Alan (California Radiant) Forbes

The 26-99 is rated for 2.18 amps and it was drawing 1.8 amps. I took it apart and found this. The strange thing is that the system was not acting like it didn't have a pump, i.e. the boiler had long burn times and most of the zones were heating.

Nevertheless, I was so happy that I found the culprit, but when I turned on the system with the new pump, it acted exactly the same. Partial heating of the ceiling in the living room and boy's bedroom and no heat in the dining room and entry. The amp draw on the new pump is .3 amps below what's stated on all 3 speeds and I don't quite know how to interpret that.

GroundUp

Oh dear, that looks a bit scummy! I wouldn't suspect the circ being a major factor here as it's serving the rest adequately. Is it possible that there's some sort of monoflo/venturi feeding those areas that's been gummed up and now being bypassed? Or possibly a hidden manifold somewhere that's not allowing flow through certain loops due to airlock or buildup? I may have misunderstood what you said earlier regarding the purge, but if there is indeed flow through these specific loops when purging, there would be flow during operation as well. I ran into something similar a few years back and ended up filling a barrel with hot water then watching with thermal imaging to see where the fluid was going. I found a mishmash of tees buried in a wall that was intended to be a manifold at one point, but during the boiler swap 2 of the 3 had drained back and become airlocked. I had to add valves to each individual loop to force that air out.

Mustangman

I'm not sure exactly what you have but I'm going to throw a few things out there. First, do your manifolds have isolation valves and flow meters built into them? Either way, when you purge, you have to have the return to the boiler off. If you don't there is nothing to stop return water from the boiler from backing into your manifold, you may be purging but you may just be pulling water from the boiler return. You have to force the water to go where you want it to go. So with the return off, purge each loop individually. Think about it. we are forcing water through the tubing and catching it on the return side. It has to have all the air out if you purge each loop with the main return off.
Again, with the return off, and supply open. if you get no flow on a loop, its cut off or plugged somewhere.
I have been called out on jobs for this same issue. They just purged it wrong and were pulling return water, without any air because it was right from the boiler return and not the loop.
Water follows the path of least resistance, which would be return water from the boiler, not running through 300' of tubing. Thats a good one to remember.
Good luck.

hot_rod

To purge multiple loops at once you need pretty good flow. Probably more that any 1/2" fill valve could provide.
So sometimes a purge cart, or connect a garden hose with street pressure to get up around 10 gpm, can make the difference in a stubborn purge case.

Alan (California Radiant) Forbes

We had a pretty good purge set up. The fill valve had a bypass, but it was pretty weak. The boiler room is in the middle of the basement, so we ran about 30' of garden hose through the rec. room from a hose bibb to the boiler and then another hose outside for the drain as there was no floor drain in the boiler room. The water pressure is 75 psi and we had strong flow out the discharge.

As far as a manifold, I can't find anything and I think they are imbedded in the plaster or framing. It's a big house and there are areas that I haven't seen.

hot_rod

You can always check flow by filling a bucket with the hose before you connect it.
Any idea how many loops or zones you are trying to purge together?

If the bucket fills in a minute you will get less than 5 gpm through the system due to the pressure drop through all the loops. A good 1/2 hp purge cart would get you 10- 12 gpm at 50- 60 psi. With 3/4 hoses on the cart.

It could be with many loops you just aren't getting enough flow through long or partially clogged loops, from the hose supply?

Alan (California Radiant) Forbes

Any idea how many loops or zones you are trying to purge together?

One zone at a time with 4 or 5 loops.

A good 1/2 hp purge cart would get you 10- 12 gpm at 50- 60 psi.

On older systems with copper tubing, I don't like going above 30 psi. I'm concerned that thinning spots in the copper tubing might let loose.

If air was a problem, you'd think I'd get a decimal of air when purging, but I got absolutely none on any of the zones.

Teemok

With that muck in the the pump, I fear what's in the pipes and boiler. You might have clear flow paths on the zone purge side but have you confirmed needed flow through that old copper coil Burkay? I'm assuming it's primary only piping. If your zone piping has low flow conditions from design due to large piping or large loop imbalances that requires high flow for the longest loop to see a minimum flow, a clogged boiler will expose the imbalances as no flow in long loops. Think loops need 10 gpm, boilers only letting 6 gpm through. Clogged air separator?
I worked on an Eichler Burkay that I was asked to service. Reluctantly I cleaned the fire side. Found it badly scaled up. It didn't cycle much, very low delta T not from flow, heat just went up the flue.

DCContrarian

A failure isn't someone who sometimes fails at things. A failure is someone who doesn't learn and move on when they fail.

That said, I'd be looking for ways to isolate loops and see if you can force flow. If you can isolate a pipe from ground, I've had some luck tracing pipes in walls using an electrician's wire tracer.