Poor heat output - old painted radiators - hot water system

todd_14

Thoughts on what can be done to increase heat output on 1st three (large) cast iron radiators on 1st floor zone?

I have a 3 zone hot water system in an old 1872 home. 

House has 3 zones fed by gas W/McC GV90-6 boiler with 3 individual taco 015 3 spd pumps running in low. 

Boiler temp is set to 180. 

Each zone is is feed by a 1-1/4” Cooper feed loop (plumbed in 1950’s using monoflo tees at each radiator) with individual circ. Pump.

these 3 radiators are the 1st on the 1st floor zone loop with a total of 7 cast iron radiators on the loop.  The other 4 on loop are smaller in size. 

These 3 radiators get hot but do not give off huge amounts of heat.  I have propped open the hinged top on the enclosures to get more heat out of each. 

each radiator is fed off copper loop using monoflo tees and 1-1/4” copper connected to original black iron pipes at radiators. 

All 3 radiators have lots of peeling paint and dust.  Radiators are painted white with large areas of exposed cast iron and large areas of flaking off (but attached) paint. 

on 1st floor zone , the 1st 3 cast iron radiators are very large (26” h x 8 deep (5 tube x 28 sections (66” long.). 

Each radiator is in a factory produced steel enclosure with mesh fronts, solid sides to floor and hinged steel lid with insulation on inside of lid. 

Enclosure is 10” wide or so providing less than 1” clearance in back, 1-1/2” clearance to from mesh and 2” clearance to lid. 

Front face of enclosure is 1” above floor and top edge has vent holes to let out heated air (in top cross strut of enclosure) in addition to mesh front. 

All radiators have been bleed - no trapped air. 

Control valve on each has screwdriver slot on stem and slot is aligned with piping. 

thoughts on how to increase heat output?
suggestions appreciated. 



is low output related to enclosures
peeking chipped paint
Monoflo  valves
or what?? 

See pictures. 

todd_14

Top of radiator reads around 170 degrees when boiler is running. 

bburd

170°F is about right for that type of system. Those enclosures will reduce the radiator output by about 30% with the lids on. With them off, perhaps 10% compared to freestanding radiators.

Those balancing valves are 1/4 turn from full open to closed, and from your description they are fully open.

 Perhaps try reducing the heat output on the other radiators in that zone. This can be done by reducing the flow to those radiators, or partially blocking the airflow through the enclosures if present. You could also move the thermostat to the coldest part of the zone.

EBEBRATT-Ed

If you had someone cut the top out and put expanded metal on the top. At least part of it you would get much better heat

todd_14

thermostat is close to these radiators but rooms do not heat up well 

mattmia2

Is most of the radiator at 170? Are you running setback?

ChrisJ

Radiators are something like 60% IR output and 40% convection.

Those enclosures are killing convection and greatly reducing IR.

In my opinion all radiator enclosures belong in the trash. (This does not include convector covers that are part of the design).

Get rid of the covers and clean up and paint the radiators.

Solid_Fuel_Man

I agree with @ChrisJ 

Radiator covers are good if you want to reduce the heat output of a particular radiator. If you are not getting enough heat, get rid of the covers. Paint the rads to your liking. 

reggi

Seem unanimous.... pulling the covers and cleaning would be a instant improvement ... Painting could wait until spring.. enjoy your new heat  

mattmia2

reggi said:

Painting could wait until spring..

Unless there are children that might eat what is likely flaking lead paint

Solid_Fuel_Man

Don't eat the paint chips. 

Use baby gates to keep kids away if need be. 

ChrisJ

Using baby gates to try and keep young kids away from every radiator in a house isn't really going to work.
But that said.......let's keep in mind radiators do have convection and lead dust can be carried away with the air.

Covers or not.


I have no idea how big of a problem it is, just that it can be a problem. Paint dust from doors rubbing etc is mentioned in a few articles I read.

flat_twin

My smart **** bro in law said the nicest part of our recent kitchen remodel was the newly painted rads! LOL

TonKa

A trick I've used temporarily is to aim a small fan at the bottom of a radiator to increase convection.

tim smith

Pull covers, clean up and paint.

reggi

mattmia2 said:

Painting could wait until spring..

Unless there are children that might eat what is likely flaking lead paint

Of course, while I recommended cleaning I wasn't specific to a method as there are different standards and regulations depending where you live and the occupancy.
He could EPA clean it...6mil sealing off the area with 2 chamber air lock and disposable hazmat outfit, HEPA vacuum and filtration to start ( the cabinet I would just seal up and dispose of) 
Use a wet contact method of removal for loose paint, wash , rinse , repeat if needed
Leave it like so til spring OR as it's only hot water perhaps it won't OFFGAS as bad as Steam Radiator while it cures with the heat on and windows closed...
But that's another subject 

gmcinnes

@todd_14 If you're concerned about lead paint at all, and you have kids in the house DON'T VACUUM. It just aerosolizes the lead dust and sprays it through the air and onto other surfaces.

Even if you have a fancy-dancy household vacuum that says it's HEPA, it's not in the way it need to be for lead work.

Work wet.  Clean with water and a strong detergent. Mop/wipe around the work area at the end of a session, and change your clothes and wash ASAP.

Get some test kits.  3M makes some.