Both Supply and Return risers very hot

kdshakk

Both the supply AND return riser in this one area are very hot. And my gorton #2 is gurgling and making lots of noise. I thought only the supply riser was supposed to get hot like this? Could this mean the boiler pressure is higher than it needs to be?
Thanks for any thoughts

Hap_Hazzard

There shouldn't be a noticeable difference in temperature between supply and return. The heat a radiator gives off comes from turning steam at ~212°F into water at ~212°F. (I'm saying approximately here because the actual boiling point varies according to the pressure in the system.)

Can you tell us a little about your system? If it's a two-pipe system, why is there a vent on your radiator. Also, why is it a main vent, and what's it doing on top of your radiator?

kdshakk

Hap Hazzard, Thank you for your reply. This is a very old building. It is a two-pipe system in an old grain warehouse building that was not originally set up for residential use. The boiler supplies heat to two 5-story buildings that are connected. We have had a ton of work done over the years and the situation is new with new plumbers. I remember being told n the past that the two pipes should not both be hot so I was wondering why that is the case.

In answer to your question about the gorton 2, my radiator is so long that steam was never getting to the end. There was also something about the way my radiator was piped that kept seemed to cause a problem so adding that pipe at the very bottom seemed to do the trick. All was well, for a while....



If you want to see the entire saga it is under my user name with the title "What are air banks?" I tried to insert a link here, but could not do it.

Jamie Hall

This is, technically, a two pipe system? OK. As @Hap_Hazzard noted, the return in a two pipe system will -- at least near the radiator -- be warm. Sometimes it will be very hot -- but it will not be at quite steam temperature. The return of a radiator working at full song will, however, often be within 5 degrees of the supply.

If the trap is working.

If the trap is stuck open, which happens, then the return may be very close to or at steam temperature.

All this is not guaranteed. For example, if the inlet valve on the radiator is set to allow only enough steam in to match the capacity of the radiator -- or often, in vapour systems, slightly less -- then the return temperature will be hot, but not steam hot, whether the trap is open or not.

kdshakk

Thank you. It's just odd. I have now turned off the Danfoss Tekmar controls and the radiator valve is off as well, but the risers (only those 2, the others seem fine) are blazing hot, the gorton 2 continues to gurgle and the end of the radiator furthest away from the risers (with the gorton on it) is hot, but not the other end.

Jamie Hall

With a vent on there, unless you can turn off the radiator completely (unlikely), they will still get steam.

That said, though, I sort of wonder if you have a nearby trap which is misbehaving.

KC_Jones

I just looked at your previous post, not sure how I missed that one...lol.

Couple things I see:
1. Just because some stuff is working doesn't mean it's correct. This is a system and when part of a system isn't working the entire system needs to be looked at.
2. Whoever did the TRV set up and all that re-piping did it incorrectly. I saw in one picture a radiator that was re-piped to be like a 2 pipe, but it is still a 1 pipe system. So the pipe was extended to the top, TRV added, then a return pipe on the other end. The radiator is still sloped towards the supply end so the drip pipe won't work correctly. If I am wrong about the re pipe I apologize, but that's what it looks like. Also the vent is in the wrong place (too high).
3. Adding that huge vent on your rad, while it may be helping/working isn't really proper either. The piping should be vented like it's a main, then the radiator vented (with TRV vent if desired). Also a vent on top of a rad is never correct, it will cause a short circuit to the vent and incomplete heating.
4. The system should be in top notch (perfect) working order, balanced etc. before anyone should ever consider adding TRV's. A TRV is a fix for a single overheating radiator, not a fix for system problems. I see people miss applying them on here or suggesting miss applying them and it makes me cringe. That is a significant cost for a potentially poor return.

How this should have been done is leave the piping alone, fix the actual system problems whatever that may be, could have been as simple as balancing the venting, which could have meant adding venting. After all that then think about TRV's if necessary. Also the people living there should not ever cut pipes for any reason without consulting the building as they could be disconnecting others heat, or causing all the work that was done to be voided due to all the imbalance that is caused. And then later they will complain when things don't work correctly.

I know from your posts you seem to like the original contractor, but from where I am sitting, looking at pictures, they didn't know what was going on much more than your current one does.

If this is to function as a 2 pipe air vent system (no traps), then it needs to be piped like a 2 pipe air vent system (it currently is not). If it is to be run as a true 2 pipe system, then it needs to be piped and run as a true 2 pipe system with traps and no vents on the radiators, your current piping arrangement at the rads is that of a true 2 pipe system, at least the ones I saw pictures of.

You currently have some kind of composite of the 2 and it isn't working, most likely that high pressure is forcing steam to go anywhere it pleases and causing all kinds of problems. An no I am not saying lowering the pressure will actually fix anything, it just might make the problems less noticeable. I would suggest 2 psi is still too high, but you might not be able to actually lower it with what you have going on.

kdshakk

*sigh* Thanks for your input. I'm not sure my very layman's explanations or even the pictures tell the real story. I wish I could narrate it better. The TRV has worked really well.....until now. The one in the bedroom continues to work well. The change seems so sudden. Again, thank you so much for your insights. Much appreciated.