troubleshooting hot water convectors

PeteA

I am doing a little research on convectors because my tenants say that they don't get "enough" heat from them and the rooms feel cool. The piping in the house is all original single 1" steel loop with diverter T's tapped with 1/2 (all steel) to feed the convectors. The convector elements do get warm but honestly not hot.
I bought the house back in '96 as a foreclosure and I never flushed or did anything to change or update the heating circuit so I guess the possibility of scale or other buildups may exist but I will investigate these thing further over the next couple of weeks. I installed a brand new boiler last year when I converted over from oil to gas and everything obviously ran well last year but they said the convectors were similarly "warm" but never hot. I have the pump pumping away to maximize the heat delivery and maintain good steady pressure through the loop. It's a very small 740 sq ft single story house with about 23 to 25 feet of total convector lengths being fed by a 007e pump. The boiler fires great and the return water come back hot quickly so I don't think I'm going to focus on the main loop too much. I did a long purge of the system when I put everything online last year and the water flushed pretty clear.

I guess what I need to help my troubleshooting is a baseline of:
1) Pressure - what pressure should I have the system set at to maximize the waterflows in that type of pipe circuit its currently at 12psi. I read other posts that mention 15 and another that said 20psi
2) Temperature- I have the water temp at the boiler set to 180 already, I believe I read that this was right for this system
3) Are bleeders needed on these or not some folks seem to say yes and others say no. Each one has a key type bleeder as of now.
4) the convectors appear to be copper, I see OCS has a steel version but mine are copper.
5) Has anyone ever said or shown that they were able to effectively make their own replacement elements out of multiple baseboard elements in order to replace a damaged or clogged element? I see only one or two manufacturers and nearly no place carries them in stock. The ones I have seen are pretty pricey so can 2 or 3 -3/4" baseboard elements be paralleled together to make an element.

Just throwing these out there as base questions for the experienced folks on here while I continue to do my research. I can certainly see the possibility that the piping (especially in the 1/2 taps off the diverter Tees) could have some restrictions maybe debris or rust that may be messing with the water flow but I'm just not certain at this early stage, the house did sit vacant for years before I bought it. I will bring my thermal camera with me also when I start digging in to things.
Just like my other posts, I will add more info and photos as I dig in and investigate. Just looking to pick your brains to start off in a decent spot. I never want to reinvent the wheel

hot_rod

Do you recall what pump was on the boiler that was replaced? Diverter tee systems can have quite a bit pressure drop.

If all radiators get warm, but not hot, they mostly likely have flow. Maybe just not enough.

See what temperature arrives at the first convector, and the ones down the line.

mattmia2

How hot is the main? How hot are the runouts to the convectors? The cabinet has to be around the convector for it to transfer heat to the air properly. Are the valves on the convectors open and in good condition? What air elimination do you have at the new boiler?

PeteA

hot_rod said:

Do you recall what pump was on the boiler that was replaced? Diverter tee systems can have quite a bit pressure drop.

If all radiators get warm, but not hot, they mostly likely have flow. Maybe just not enough.

See what temperature arrives at the first convector, and the ones down the line.

@hot_rod
I did originally install a B&G 100 way back when I bought the house because the existing pump was seized. I really don't recall at this point and so many years later what the original pump was. I think the B&G 100 was available at HD at the time and I just bought it and threw it in. LOL

mattmia2

Did it heat with that old circulator that you installed?

PeteA

mattmia2 said:

How hot is the main? How hot are the runouts to the convectors? The cabinet has to be around the convector for it to transfer heat to the air properly. Are the valves on the convectors open and in good condition? What air elimination do you have at the new boiler?

@mattmia2
The main was piping hot at the time I was there doing the initial install of the new boiler and getting everything up and running. I believe that it made it to the 180 degree point. I was not there at the house this season yet to see if anything has changed.

The ceiling is partially finished so I will have to check the temps at the base of each convector to see the temps coming up.

The convectors have straight pipes, no valves at any of them. I cleaned all of the convector covers last year to make sure there was good air flow.

Everthing near the boiler is brand new, I installed the discal air eliminator with the auto purge for air removal and I have the pump out in the circuit pumping away to ensure its as low of pressure as possible.

PeteA

mattmia2 said:

Did it heat with that old circulator that you installed?

great question as far as was it ever "HOT" at the convectors. It's always been a rental and it always seems like the heat is never enough for tenants. This tenant has been in there with both the old boiler and the new one and has stated the same things with each system. Yet when I check the wifi thermostat the house seems to be holding the temp its set at. Its hard to argue with since I never actually lived in the house so I don't know what they feel or not so I just wanted to go there armed with some ideas where to start and how to kind of rule out issues.
I'll immediately check the return temp on the pipe, verify the pressure, purge each convector but then beyond that there's really no other test points since there's no valves and this keeps me from being able to vary the load on the system. Limits my ability to troubleshoot which is why I was curious about the worst case if I ripped out one or two and put valves in could I make my own or am I stuck buying like and kind from the companies like OCS.

mattmia2

The convector itself is very unlikely to be your problem. You could remove one and flush it with a hose to prove that. The construction of a convector is different from fintube, it has more tubes and larger, more dense fins so it has a lot more area than baseboard element and it is sized to fill most of the cabinet so the cabinet provides proper draft through it.

PeteA

mattmia2 said:

The convector itself is very unlikely to be your problem. You could remove one and flush it with a hose to prove that. The construction of a convector is different from fintube, it has more tubes and larger, more dense fins so it has a lot more area than baseboard element and it is sized to fill most of the cabinet so the cabinet provides proper draft through it.

@mattmia2
Thanks for the additional info 'll go there and go through one at a time and see if there's anything obviously wrong with the system and then go from there.
Any opinions on the system pressure? Are these things meant to be run at a higher pressure than the normal/typical 12 pounds?

PeteA

mattmia2 said:

The convector itself is very unlikely to be your problem. You could remove one and flush it with a hose to prove that. The construction of a convector is different from fintube, it has more tubes and larger, more dense fins so it has a lot more area than baseboard element and it is sized to fill most of the cabinet so the cabinet provides proper draft through it.

I noticed the differnt design of the elements which is why I was just throwing mud at the wall to see if adding additional fin tubes inside the cabinet may help increase the surface area to help pump out more heat. I was just an idea I like to have a plan a, b ,c and occasionally a D ready.

Alan (California Radiant) Forbes

If the convectors are not as hot as the single pipe loop, there is definitely a blockage, but I don't think it's debris. Diverter tee system are notorious for air blockage in the loop to the radiator and it's very difficult to move that air to where it can be vented.

Add some Dawn dishwashing soap to the system as a surfactant, raise the pressure to 25 psi to make the air bubbles smaller and purge the system again. Sometimes this works, sometimes it doesn't. If it does work, you can thank me. If it doesn't work, blame @Mark Eatherton who's the guy that originally suggested it.

PeteA

@Alan (California Radiant) Forbes
That is definitely not something I was thinking of at all. I can't imagine how @Mark Eatherton came up with that idea.

mattmia2

For the convectors themselves, they don't need higher pressure, the pressure has to do with the height above the boiler of the highest piping. There needs to be enough static pressure in the system to push the water to the highest piping. If it is one or two story then the normal 12 psig is enough. If it is 3 story or more then you need to add some pressure for the additional height.

Higher pressure will help it remove air more easily but it isn't needed for different emitter types.

PeteA

mattmia2 said:

For the convectors themselves, they don't need higher pressure, the pressure has to do with the height above the boiler of the highest piping. There needs to be enough static pressure in the system to push the water to the highest piping. If it is one or two story then the normal 12 psig is enough. If it is 3 story or more then you need to add some pressure for the additional height. Higher pressure will help it remove air more easily but it isn't needed for different emitter types.

Ok great
i Figured the unusual shape of the convectors may give air more spots to get trapped which was why some others were boosting the pressure. But I certainly do understand the higher the water needs to be lifted the additional pressure would be required. It’s only 1 story so I’ll leave it where it’s at but just boost it a little if I need to purge the system again like when I first put the system on line.
thanks Again @mattmia2

EBEBRATT-Ed

@peteA

Get yourself a decent infrared thermometer. Shoot the temperatures along the mains and at the inlet and outlet of the convectors.

And yes monoflow systems can be difficult to remove the air. All the convectors need bleeders. If all you get is water then it's not an air issue it is a flow issue.

I wouldn't bather taking a convector apart at this stage. Debris in a convector is unlikely.

Post the btu output of the boiler and the circulator you are using and the pipe size of the main and the temp readings you are getting

neilc

question for the diverter Tee pros here,
if the boiler was mixed up and pumping into the return of the diverter system ??????
would a reverse flow thru a set of Tees try more to bypass the rad, or would it not matter?

and for the OP,
any chance you're pumping in the wrong direction ?

hot_rod

All hydronic systems go through a transitional stage when they first start. How long they are in this stage depends on the mass of the system, the match up of boiler output to heat emitter. And the load at any time

The system will strive for and reach thermal equilibrium. You can identify that condition by monitoring the swt and the return temperature. When those temperatures stabilize the system is at equilibrium. In other words the heat emitter is putting out exactly what the boiler is capable of .

the condition may not be what you expect

Get a comfortable chair and sit and monitor the system for 30 , 60 minutes or more

Azel makes a nice dual temperature gauge with strap on thermistors. It displays both temperatures and the differential

Steamhead

@PeteA , are the convector elements clean and free of dust? If not, this would block air circulation and reduce their heat output.

PeteA

Steamhead said:

@PeteA , are the convector elements clean and free of dust? If not, this would block air circulation and reduce their heat output.

This is certainly something I will be checking since I know that air flow through the convectors is critical Thanks

PeteA

neilc said:

question for the diverter Tee pros here,
if the boiler was mixed up and pumping into the return of the diverter system ??????
would a reverse flow thru a set of Tees try more to bypass the rad, or would it not matter?

and for the OP,
any chance you're pumping in the wrong direction ?

I don't believe so since I was pretty careful when I did the plan for replacing the boiler to make sure that I went back pumping and connecting everything the way it was originally installed. I did improve on the configuration by pumping away from the boiler when I did the piping instead of pumping towards the boiler the way it was originally installed. But I will certainly check again.

PeteA

EBEBRATT-Ed said:

@peteA

Get yourself a decent infrared thermometer. Shoot the temperatures along the mains and at the inlet and outlet of the convectors.

And yes monoflow systems can be difficult to remove the air. All the convectors need bleeders. If all you get is water then it's not an air issue it is a flow issue.

I wouldn't bather taking a convector apart at this stage. Debris in a convector is unlikely.

Post the btu output of the boiler and the circulator you are using and the pipe size of the main and the temp readings you are getting

Thanks I actually have access to several Flir devices with really broad temperature readings and displays that I will be bringing with me. I'll leave the bleeders in place and make sure its not just a trapped air issue limiting the flows.

PeteA

hot_rod said:

All hydronic systems go through a transitional stage when they first start. How long they are in this stage depends on the mass of the system, the match up of boiler output to heat emitter. And the load at any time

The system will strive for and reach thermal equilibrium. You can identify that condition by monitoring the swt and the return temperature. When those temperatures stabilize the system is at equilibrium. In other words the heat emitter is putting out exactly what the boiler is capable of .

the condition may not be what you expect

Get a comfortable chair and sit and monitor the system for 30 , 60 minutes or more

Azel makes a nice dual temperature gauge with strap on thermistors. It displays both temperatures and the differential

That Azel device does look really simple and is a really clean looking device. I'll use the Flir cameras for this investigation and if I don't get anything precise enough this may be the option to just strap onto the pipes and let it do its thing.

EBEBRATT-Ed

@neilc

If you reverse flow and pump into the return the diverter tees would be on the rad supplies. Should still work. He is getting flow because he said the supply and return are hot at the boiler.

Sounds like he is air bound or needs a larger pump if the supply and return to the rads are not hot. If he is bleeding air at the rads it's an air problem. If he bleeds water its a flow problem (larger pump0.

But checking for reversed flow as you mentioned is a good idea. Sludge and debris is seldom a problem in a closed loop system unless new water has constantly been added over the years.

In my house which I sold 3 years ago I left all the piping the same and installed a new boiler and added an indirect and a new 007 pump and 2 zone valve 1 for the indirect and 1 for the heat.

When I started it the heat was very sluggish, and the water was not moving well. The zone valves were Honeywell 1" and I think the Cv on the valves was 4or 5 can't remember.

I swapped the valves for Taco which had about an 8Cv and it was fine after that. Not a big house 1000 square feet and the main was 1 1/4" copper. Way oversized for the 50,000 heat load.

But the 007 couldn't move the water very well until I swapped out the valves.

So diverter tees are restrictive, and a few small changes can throw it out of wack.

PeteA

EBEBRATT-Ed said:

@neilc

If you reverse flow and pump into the return the diverter tees would be on the rad supplies. Should still work. he is getting flow because he said the supply and return are hot at the boiler.

Sounds like he is air bound or needs a larger pump if the supply and return to the rads are not hot. If he is bleeding air at the rads it's an air problem. If he bleeds water its a flow problem (larger pump0.

But checking for reversed flow as you mentioned is a good idea. Sludge and debris is seldom a problem in a closed loop system unless new water has constantly been added over the years.

Thanks @EBEBRATT-Ed
I'll go at it slow and check everything since I want to be able to fix it right and then set it and forget it for another season. Definately ha great flow last year because the pipe came back piping hot pretty quickly last year when I started the first heating season i installed it all.

hot_rod

On copper pipe, sometimes the infrared cameras don't read accurately. A dab of flat black paint, or a wrap friction tape on the pipe to shoot at can help. Nothing shiny.

mattmia2

Or get a clamp on probe for a meter or thermometer.

hot_rod

A nice feature of the Azel I mentioned is it has a large battery, but can also take a 24v input if you plan on leaving it on a system

it captures high and low temperatures also

Hard to go wrong for 68 bucks

clammy

Being I ve worked on similar type system I would make sure the manual air bleeders are on the correct side . Seen them on the inlet side of a convector and no matter what I did it purge pressure wise it refused to bleed finally drain system and installed the manual bleeder on the correct side and all was good . Over the years I ve found that all systems can benefit from the circulator being installed pumping away from a good micro air eliminator and your expansion tank make up water feeder . This especially true on system which have decent pressure drops mono flow systems and reverse return system and two pipe direct return systems as for simple baseboard loop system they seem to work 90 percent of the time no matter where the pump is but when installed on the supply it’s clearly a step up on many levels and those who don’t get well they usually don’t understand a stick drawing so they will never as they say get it .
Even though your system is existing have you check the pipe and distances between your mono flow tees to short a distance and not enough pressure will lower flow to that convector .another quick point is ,is this a 1 st or 2 nd floor radiator .the further the distance from the main the more pressure drop required the more distance between tee or the use of two divert tees. Many strange things happen in mono flows and sometimes it’s from the day it was installed ,I had one where the plumber at the time refused to the spend money on proper mono flow tees and used reducing tees seeing they where much less money the outcome was terrible for decades . I finally corrected by installing the correct tees and the correct distances and all was fine there was heat on the second floor convectors for the first time since the couple lived there like 20 some on years . There always a reason stuff doesn’t work correctly it usually takes a little bit of knowing what you’re looking at and looking around like a detective and using a little bit of deductive reasoning to find the issue .
Another little kinda fact when having multi zone systems and one is a mono flow and the rest baseboard zones do your self a favor and install a seperate pump for the mon flow other wise the only time you will have the proper flow though the mono flow is when it is the only thing calling when baseboard calls ( with out flow rafters or balancing valve ) they will see the flow while the mono flow see less then optimum flow or pressure due to flow going through the less restrictive zones . Some will never notice it due to the mon flow just keeps calling and eventually the baseboards zone cycle off and flow goes back to the mono flow and finally those last convectors get some heat . Just an observation from time in the field and doing exactly what I ve stated and ending up w happy satisfied customers . I ve done this on job for about 20 years or so .
Peace and good luck just food for thought
Clammy

PeteA

@clammy thank you very much for the guidance.
Fortunately it is only a single story house and tomorrow when I go there I will be doing all of my detective work to verfiy the direction of flow and where the bleeders are actually mounted compared to the direction of the flow. It's a small square house so I don't even believe that the single pipe loop is split but I will be looking for hidden valves or tees.
The basement is partially finished but I believe I have enough access points to poke my head up into the ceiling to see which direction the monoflow Tees are and approximately the spacing. I'll be taking some notes and making a sketch so that in the future I know where things are in case I need to get deeper into the piping.
I wouldn't be surprised if I get into things if I find something hidden in the ceiling that may have hampered the air bleeding / purging or some other unexpected modification someone may have done.
I'm hoping for the best but prepared for the worst. I'm trying to keep my mind open for anything especially something simple so that I don't get locked into looking at one thing and missing the obvious issues.