Upgrading old radiators - worth it?

SeanGMac

Hi,

I have an old, draughty, log-built house. Been here 20 years and the radiators looked pretty old 20 years ago. Log-burning boiler heats the water and radiators. Had a new, bigger pump installed several years ago. About 10 years ago I manually flushed all the radiators and we changed the pipework from copper to pvc. About 5 years ago we had a new radiator added to the circuit in an unheated part of the house. Boy - that new radiator rocks, and it is much smaller than the older ones elsewhere. Now I am thinking I should go the whole hog and change them all to newer models.

Does anyone have experience of doing this and are you satisfied with the results? Seems to me to be an expensive risk. Any experiences will be gratefully received.

KC_Jones

I think we need pictures of the radiators in question. A radiator is an empty vessel that you put a warm or hot fluid into. I'm having a hard time understanding how a new one will work better than an old one. Pictures of what you are using could clarify what's going on.

SeanGMac

Here is a picture of a particularly troublesome one in the kitchen. I have to bang the crap out of it with a hammer to get it warm most days but it's not essential as we have other heating there. Then a picture of the newer little one.

mattmia2

I don't see what a hammer is going to do other than dent it. Perhaps the TRV is sticking.

PVC?

PC7060

mattmia2 said:

PVC?

My thoughts exactly. Copper is a great piping option, did you really switch out to PVC?

Since PVC allows air into the system I’d think corrosion of the pump and boiler would be a big issue. 

The two rads in the pictures looked like they are plumbed with copper. Can you give us pictures of the boiler and other piping?

JakeCK

If he switched out everything to pvc 10 years ago I wanna see this. 

You're not even supposed to use pvc for domestic hot water.  

PC7060

Is it April 1st? 

maybe the OP meant pex?

GW

Sean that head should come off and you’re gonna see a small pin (tiny shaft), that’s the valve. The “head” attaches to the valve. Normally the pin is “out” and the TRV head closes on it as the room warms up. Seems like the pin may sticking shut. Where are you ? Doesn’t look like traditional USA piping 

bburd

Looks like European or United Kingdom radiators and piping practice.

psb75

First pic looks like a "gen. 1" panel radiator. This also does not look like a U.S. install. (I don't recognize the copper connection on the (painted) copper 90 on the old rad.) Your flow problem in this rad is most likely the TRV valve with a stuck pin. Panel rads will work best if supply and return are on opposite sides of the rad.--one bottom, other top connection.

SeanGMac

Thanks for the comments so far. So we are not in the States but in Finland. It's cold here in winter, very cold, and sometimes very, very cold. Minus 30C is not uncommon, at the moment it is minus 10 and it is barely December.

Starting at the beginning: we get our water from a well which seems to have a high mineral content. When we first moved here I got the plumber in to check the rads as the last two in one line just did not work at all and we got a bigger pump which did seem to fix that problem. However, we were having to get the plumber out every few months to replace bits of piping all over the house which would spring leaks (usually bends) and this was, apparently, due to water corrosion. Also, when I flushed all the radiators - i.e. took each one into the yard and fired water through them - there was a lot of silt coming out. I expect in the years since they have again silted-up a wee bit. Hence the banging with a hammer and believe it or not it does work. Anyway, our plumber suggested replacing the very thin copper piping along the run with this plastic stuff which is much wider than the original - I call it pvc but I don't really know what it's proper name is.

The thing about the new vs old radiators is that the new one just performs so much better than the older ones - i.e. it throws out heat, you can feel it a few feet away whereas the original ones, even when they are hot to the touch, they don't seem to radiate that heat in the same way and I was guessing it was something to do with the technology of the radiator. So I was thinking that if radiators nowadays are all singing and dancing it would be a sensible investment. On the other hand that money might be better spent on a new boiler.

Btw I have posted on similar website forums in Finland but got little in the way of feedback.

PC7060

"Anyway, our plumber suggested replacing the very thin copper piping along the run with this plastic stuff which is much wider than the original - I call it pvc but I don't really know what it's proper name is."

So that's probably PEX, hopefully one with oxygen barrier.

Are you having problems with circulator failure due to corrosion.

And Finland, you are definitely are in cold area. Nebraska where my family is from gets down to -25C but fortunately not that often. But the wind.....

bburd

The problem is not with the radiators themselves. I suspect you have restricted flow in the older parts of your system due to sediment mucking up the valves and perhaps narrowing the piping.

SeanGMac

To bburd - so how would that issue best be resolved?

bburd

SeanGMac said:

To bburd - so how would that issue best be resolved?

I will defer to the contractors on this site who have more experience with repairs. Although I have some experience in diagnosing and evaluating system problems, my career has been on the design side of the industry.

SeanGMac

So I have had, perhaps, one useful response on a site in Finland and I would appreciate your measured expertise on this response because, otherwise, I am preparing to go FULL-RAMBO on my plumber:

you do know that every radiator has two valves. the one you can adjust by hand (or via thermostatic radiator valve) and a second one for balancing all the radiators in the house. When the system is installed this second balancing value is adjusted by the engineer to make sure the radiators near the boiler (which get the hot water first) don't get too hot at the expense of the radiators later in the circuit (the water gets less warm as it travels from radiator to radiator). This adjustment is only done once and is called "balancing" because it's balancing the heat output across all the rooms.

one explanation is that the balancing valve (also known as the lockshield valve) is adjusted differently on your new small radiator and it gets more than its fair share of hot water. If you google for "how to balance radiators" you'll see that they're all supposed to warm up at the same rate and balancing means checking the temperatures of each one.

When you had the small radiator installed did the engineer rebalance all the radiators (including the new one) or just add it and open the lockshield value 100% on the new one?

bburd

The above is good advice and certainly the easiest thing to check. North American systems don’t usually have individual radiator balancing valves, so that didn’t occur to me; my suggestion of sediment in the system is based on your comments above.

psb75

There are significantly DIFFERENT European and N. American operating principles being bandied about in this thread. It is getting confusing. Since you are in Europe you'd best attend to those plumbing practices. N. Americans use European panel radiators, and fittings but use different plumbing strategies. You'd best use a local plumber who understands the principles and components of your region rather than "cobble together' an international cluster f____."