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Hauserplb
Hauserplb, Plumber
Category: Plumbing
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Experience:  Over 20 years experience. Third generation
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What to do no heat in most upstairs radiators, a new condition

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What to do? no heat in most upstairs radiators, a new condition in the house. All vent valves are good and working, main valves have been replaced, heat is set at 71 degrees with a new thermostat (just on and off type, no programming). Burner responds to thermostat correctly, I have increased the pressure setting, no change.

Thank you [email protected]

Hauserplb :

Do you have a zoned system? Is it a thermal circulation or pump driven system?

JACUSTOMER-6qvgej7e- :

one zone thermal circulation, prior to this heating season all radiators responded perfectly

Hauserplb :

When was the last time the chemicals were checked?

JACUSTOMER-6qvgej7e- :

there are no chemicals used in this system of 1937 vintage, original oil heated, 1985 converted to gas always working great.

Hauserplb :

Ok, there are one of 2 situations here. Either you have a blockage due to build up (rust, calcium) or you have an air bubble.

Hauserplb :

Do you have a one way check valve in your system near the boiler?

JACUSTOMER-6qvgej7e- :

the radiator on which i had a rust problem is working well, air bubble makes sense, but I vented well and changed all water out of boiler as well, where could die air bubble be?

JACUSTOMER-6qvgej7e- :

I have 2 main vents after boiler, after both the pipes heat normal

Hauserplb :

If there is any kind of a trap in the piping ( a high spot that does not drain well) it could hold air.

Hauserplb :

However, if you had a rust problem that is leading in the direction of a blockage

JACUSTOMER-6qvgej7e- :

I agree, but the rusted pipe is heating well, I fixed the same with a sleeve over it for this season, there are no large particles which have left this pipe,

Hauserplb :

But it's on the backside of this area that is not heating correct?

JACUSTOMER-6qvgej7e- :

the highest spot in the house i can find is a upstairs radiator which used to be the hottest in the past but now just barely heats. Removing the vent on this one does allow steam to escape but not at any great rate. Also the radiator in garage, a midlevel radiator, will give lots of steam if I turn the thermostat to 75 and remove the vent just for testing, nearly cold otherwise.

Hauserplb :

Yes, I would say you have a blockage. It's causing a reduced flow rate in your system which is disabling the heating capacity of your more remote readiators.

JACUSTOMER-6qvgej7e- :

actually the pipe repaired is the only really hot one in the midlevel

Hauserplb :

My first guess it the blockage is at the first fitting on the back side of that repaired pipe.

JACUSTOMER-6qvgej7e- :

this heating problem started before i did anything to this pipe, and what do you call the back side of any pipe?

Hauserplb :

The backside is the downstream side of the pipe. My guess is that rust from inside the system broke loose and lodged in the downstream fitting. This caused a pressure spike in the system that caused an already weak (rusty) area of the pipe to start leraking.

JACUSTOMER-6qvgej7e- :

The pipe I repaired, temporary, is a midlevel area of the 3 levels in the house, and does heat. Where could the blockage bee, how do I find it.

JACUSTOMER-6qvgej7e- :

Also, would it be wise to turn of this radiator to eliminate the pressure loss?

Hauserplb :

You'll have to isolate the areas. Best bet is to go to the first cold radiator and work your way back..

JACUSTOMER-6qvgej7e- :

I mean turn off this radiator, sorry

Hauserplb :

No, there isn't pressure loss in the system as far as the boiler is concerned it's a flow problem , not a pressure problem

Hauserplb :

You could try to back flush the system , but that may do more harm than good.

JACUSTOMER-6qvgej7e- :

This pipe is fed separately from a main right after the main downstairs vent, so I don't think this pipe influences other take offs from the downstairs manifold.

Hauserplb :

I thought this was a thermal loop?

JACUSTOMER-6qvgej7e- :

How would I be able to find the blockage? other than removing pipes and radiators?

Hauserplb :

There is no way other than removing pipes and radiators

JACUSTOMER-6qvgej7e- :

It is, just has several pipes leading through out the house after the boiler

Hauserplb :

oh, ok

Hauserplb :

Sorry I can't give you better news on that front

JACUSTOMER-6qvgej7e- :

I understand, that is if we are certain this is blockage instead of any other problem

Hauserplb :

Based on what you have told me, I am very sure that is your problem

Hauserplb :

If I was at your house right now, I would be getting out my pipe wrenches to start pulling things apart.

Hauserplb :

Word of warning, those old pipes can come apart REALLY hard. Have a torch handy to heat the fittings.

JACUSTOMER-6qvgej7e- :

Than I have to wait till after the heating season to methodically remove each radiator an look . I could remove one at the time now and blow thru and reinstall, but what about the pipes?

Hauserplb :

you could cut the piping loose at the main feeder line (so you only have on pipe to replace and a union fitting to buy) and blow through the line at the radiator.

JACUSTOMER-6qvgej7e- :

Also what should the pressure adjustment at the boiler be at?

Hauserplb :

what boiler do you have?

JACUSTOMER-6qvgej7e- :

it is a Wheil Mc Lain

Hauserplb :

that's it's BTU?

Hauserplb :

model #

JACUSTOMER-6qvgej7e- :

max psi 3.0 steam 15 Psi, Size P-566-3 relief 168

JACUSTOMER-6qvgej7e- :

Honywell control setting 2.5

JACUSTOMER-6qvgej7e- :

CP No 071126

JACUSTOMER-6qvgej7e- :

i can't find a BTU rating I will look again

Hauserplb :

well, you have your answers there max 15psi

Hauserplb :

max psi for water pressure is 3

JACUSTOMER-6qvgej7e- :

the answer to the btu, but where would be a valve small enough to be effected by small rust particles?

Hauserplb :

these aren't necessarily just particles, they could be pieces just small enough to travel down the piping.

JACUSTOMER-6qvgej7e- :

the two main pipes leading away from the boiler with new vents are hot ,

JACUSTOMER-6qvgej7e- :

travel down the piping and get hung up where?

Hauserplb :

On any elbow in the system. like I'd said you'll have to start looking on the back side of the last functional radiator.

JACUSTOMER-6qvgej7e- :

you are saying backside, so what is the front? I have only one pipe leading to each radiator?

Hauserplb :

Elbows are a common area to gather debris because of the change in direction. Also, it's where the endo of a pipe was tooled. If the pipe fitter didn't properly clean the pipe after cutting a threading, it could cause a hang up.

Hauserplb :

You don't have an outlet pipe?

Hauserplb :

So it's not a thermal loop system. It's a condensate reclamation system

JACUSTOMER-6qvgej7e- :

Well it did not for 73 years, but I grant you the plumber installing this system ran right under the house with no crawl space, so good luck looking. No, there is no outlet pipe but the lowest pipe in the basement returns to the boiler, this pipe used to be hotter as well.

JACUSTOMER-6qvgej7e- :

Yes you are right from what I can tell, but heat does rise, so there is thermal, right?

Hauserplb :

Yes, but the in and out comes from the same pipe

Hauserplb :

It uses a system where the steam is at the top of the pipe, and the condensate runs on the bottom side back to the boiler.

Hauserplb :

However, this really does not change the diagnosis. I still believe you have debris in your line. It' just changes how you look for it.

Hauserplb :

Instead of looking for one point to solve multiple radiator problems, you will need to search for each plug individually

Hauserplb :

Though, you can check each radiator and guage the pressure at each, to see how bad the plugging is.

JACUSTOMER-6qvgej7e- :

Yes the bottom and top of the boiler are interconnected, the bottom pipe is just raised a foot or so before joining the boiler

JACUSTOMER-6qvgej7e- :

Do you mean remove radiator and attach a gauge to the tread of the removed radiator in?

Hauserplb :

either that our you could loosen the bleeder valve slightly and take a quick note of the pressure.

Hauserplb :

though please don't don anything to harm yourself, this is steam after all!

JACUSTOMER-6qvgej7e- :

In the upstairs bathroom, there is no heat at all, it is the opposite from the bad pipe, lets assume there is no pressure on this one, the pipe to this bathroom comes straight up

JACUSTOMER-6qvgej7e- :

there is no pressure out of the removed vent.

Hauserplb :

From that point you will have to back trace the line and check where there is pressure. If you are willing to do it, on way is to drill a whole in the line at intervals (ussually between elbows) to see if there is pressure. You can repair these holes with a "band-aid" clamp. Though you would have to reduce the pressure to safely do this.

JACUSTOMER-6qvgej7e- :

when I drill into the pipe I will drop chips into the system, by greasing the drill I can reduce this, but if there is any heat the grease will disolve!

Hauserplb :

The every small shavings are not what you are concerned with, it's the larger pieces that are causing the blockage.

JACUSTOMER-6qvgej7e- :

So I better start digging under the house!

JACUSTOMER-6qvgej7e- :

Thanks for tonight!

Hauserplb :

Sorry.. I spent 3 days with a trenching shovel under a house when I was 12, I know what your in for!

Hauserplb :

Good Night!

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