Problem with Monoflo system

Dany · October 2005

Hi,

Im new to the forum and I dont now much about heating or plumbing so please excuse my ignorance and the long post.

Two years ago I bought a house that was built around 1951. Its been 2 winters already, and I have noticed that many of the radiators are cold or at least not hot enough. The house is in the Northeast (Long Island). On the coldest days the system cannot keep up with the cold; although my thermostat is set to 72F or 70F, the system only gets to 65F or 66F.

I know that insulation is not perfect but that alone doesnt explain the cold radiators. My plumber helped me both winters with the bleeding of the radiators, thinking that the problem was air in the system. Meanwhile I think that Im spending double the gallons of oil than my neighbors.

Since my boiler is very old, probably more than 30 years, I asked for quotes to replace it, thinking that I may recover the investment in about 5 years. Along with the quotes I was told to replace all the piping, and install new baseboard panels.

Because of the cost of going along with this plan I started researching online, and tried to identify what system I have. After two weeks I can say that I know with certainty that I have a Monoflo system. There is a 1¼ main line that pretty much runs along the perimeter of the house except for one area. Each radiator is connected to the main line through a feed fitting, 1/2 pipe and a return monoflo fitting. All radiators are in the main floor. The main line is in the basement.

To my surprise I saw what seems to be a bad attempt to install an additional radiator. There is an area where the main line doesnt run along the perimeter of the house, but there is a radiator in that area (dining room). That radiator is not connected to the main line like the rest. Instead, the main line is reduced from 1 ¼ to ½ and 1/2 goes to the radiator and comes back to the line through a ½ to 1 ¼ fitting. No Monoflo is used in the piping for this radiator; its all just regular fittings.

So Im all excited that I think I found whats going on, but I would like to get your opinion.

- Would the reduction of the main line explain the cold radiators in the system?

- If I take that radiator out and reconnect the two main line segments (they are just 6 apart) will the system work fine again? Do I still have to think about replacing the boiler? And the old and dirty radiators?

- If so, whats the right way to install that radiator? It is about 40 feet from the boiler.

Thank you all in advance.

Uni R · October 2005

Many issues

The cold radiators/baseboards result from them having air inside. Do you have bleeder valves on each baseboard? If so, learn how to bleed them. Do you have a modern diaphram type expansion tank (as opposed the old large conventional type of tank)? If you don't, air bubbles tend to go into suspension and migrate from the tank to the HWBBs. I would recommend a diaphram tank for most cases.

That dining room radiator should be hot at least! ;-) You should have a monoflo for that rad or at least a bypass that you can control the flow through. As for your boiler, you may want to ask whoever services your boiler about how efficientlty it is running. If it is running fairly well then you will be far better served to first address the insulation, window and door issues where you will get a much better return on your investment.

Jay_17 · October 2005

for clarity

It sounds like you might be saying that the new radiator is not T'ed into the loop, but is actually plumbed into the primary flow path. If that is indeed the case then I bet you did find the culprit. If the flow in the 1 1/4 loop is being restricted by going through 1/2 pipe the monoflo tees probably will not work at all. I found a similar problem in my own baseboard loop system, a kickspace heater with a 1/2 inch coil was plumbed directly into a moderately long loop of 3/4 pipe, it worked but struggled to deliver the btus. I replumbed the heater with a monoflow tee and I am waiting for the cold weather to judge the improvement.
Good luck!
Jay

soot_seeker_2 · October 2005

True

Thanks for the clarification; thats exactly what I saw.
Dany

Neil_5 · October 2005

Long Island

I am a homeowner, with Monoflow and boy did I educate myself on its operations, air etc and I cleaned up most of my system as well.

Do you have convectors? Recessed wall convectors? I am in Bellmore, where are you located?

Going from 1.25" main to 0.5" inline for the dinning room heater is causing flow problems. Flow is critical for monoflow system. Actuall to think of it I love my monoflow, when designed correctly and balance give off great uniform heat and when coupled with an outdoor reset.

Neil

Dany · October 2005

East Meadow

I'm in East Meadow. Bellmore is a very nice area.

Yes, I have recessed wall convectors; I didnt know the technical name so I was calling them radiators.

Do you think that if I take out the dining room convector and reconstruct the main line the system will be back to the right balance?

I like the idea of an outdoor reset. Do I need a Buderus type boiler for that?

Thanks a lot,
Dany

Neil_5 · October 2005

Line

Dany:

Taking out that unit will help ... a ranch or split level? If you are thinking of throwing out any convectors I am looking for one of the covers for the small units.

They are called convectors and they DO put out a lot of BTUs.

Is the dinning room convector the first on the line from the boiler (meaning hotter water).

Outdoor reset is very nice especially in mild weather like now where you can keep the water at 140 instead of 180.

Tekmar have nice products and they are a few others, I added a Tekmar 256 to my system and love it.

Where in Eastmeadow? I grew up on Merrick Ave in Barnum Woods.

Neil

Big Ed · October 2005

Problem Found

Yes that reduction of the main is the reason you can not heat your home on cold days. I see that mistake every Winter. That section of radiation needs to be repiped correctly...

The Buderus with the reset is a nice choice. I have one in my own home. It was a good investment.If you would like one email me I would help you out.

Dany · October 2005

Convectors

Neil.

Thanks for all the information. The house is a ranch.
I live on Wilson Rd, a few hundred feet from Merrick Ave.

If I end up replacing the convectors with something that doesn't use the covers I'll give you the covers.
Right now I'm trying to determine which single change in the system will give me the best return while keeping the house warm.

The dining room convector is the second on the line.

What boiler do you have?

Dany

Dany · October 2005

Large open area

I took down a wall that separated the dining room/living room from the kitchen. Between the kitchen/dr/lr and the entry hall I have an open area of about 600 square feet attended by 4 convectors. I haven't done a heat loss calculation, but I wonder if 3 convectors will be enough to cover the area.

Is there a way to redo part of the piping so that I can keep the dining room convector?

Big Ed · October 2005

Convectors

I would be more concern with the balance of the rest of the home. Most system from the fifties were over sized and only one zone. Most Mono flows from your area were well balanced , except the split level and the ranch with the bumped out master bedroom. If you cut out a convector from the dining room near the thermostat , the bed rooms would end up warmer, not too much of a problem we can rebalance by cutting down on convection. But If the thermostat is in the hall way of the bedrooms, the dining room would be colder... May need to zone or add larger radiation.

The big problem is cutting the main down in size. Cutting the btu flow of the whole system by reducing it down to a 1/2" pipe. ...The main needs to be restored back to it's proper size. The dining room could be hook up monoflow, With tees...

Dany · October 2005

Distance between fittings

To add the dining room convector the main line was cut at A just before a corner where the line makes a right turn, and continues at point B just after that corner. So A and B are at about 1 foot distance.

If I want to restore the main line and install feed and return monoflo fittings, I couldnt just do it at A and B because the distance between the fittings would be less than the length of the convector (about 3 or 4 feet), right?

Neil_5 · October 2005

Re-pipe

Dany:

I have a split level from the 50s and the monoflo is well balanced, except for the mst bath which was remodel before I took ownership and they replaced the convector with regular BB, I then replaced with a Buderus Panel Rad.

I have a Series 2 gas boiler (Burnham) very nice and simple. After installation I became educated on controls and heatloss etc. Should I do it again I will go with the Buderus. I added the Tekmar 256 control and thus have nice uniform and comfortable heat with almot 90% constant circulation.

One problem I had with my system that I fixed this summer was the valves on the convectors, they turn 45deg to throttle the flow, all were leaking, and I needed all of them in the open position. So I replaced all the valves, actually took them out and piped straight into the convector. Flow is better as some were stuck in semi close position, which you should be aware of as well.

You main problem as you said the "hacked" radiator is first on the line and started with 1.25" line to 0.5" line then back to 1.25" is a big NO NO for monoflo.

You can email me off line if you need to talk more about this.

In order to keep the dinning room convector you have to plumb with mono Ts like the other convectors.

One thing I did to help my house was upgrade the envelope, I sealed all the windows, around all the doors, replaced all the wooden basement windows and seal/stud and insulate the basement. Then I added R25 insulation to the attic to total R50 (this made a big difference in my gas bill). I did all the work so the savings was even greater for me.

Good luck and if your boiler is 30 yrs old, first fix the envelope, then a heatloss (we can do this easily with the free s/w I got from here) and THEN size a boiler for your system and of course balance back the monoflo system.

If you need a pro, I got one from here for my brother who installed a Buderus system and the work they did was ART!!!!

Neil

Neil_5 · October 2005

Distance

The smaller the distance between supply and return the lower the flow. Radiators above the lines can be spaced as close as 6 inches (this I read here on the Wall). Radiators below the line needs to be spaced at least the width of the radiator. Now your DR radiator is above the line, so you can space less than the width of the radiator. NOW, since the radiator is second on the line, depending on the size of the radiator the orginal installations would have space the Ts closer in order to balance the heat output (the water is hotter since closer to boiler) you follow?

Are you good at soldering copper? and know how to drain and refill your system and remove air from the system?

Neil

Uni R · October 2005

Sort of...

You could put a valve in between A and B and then use it to adjust to the point where you have sufficent water diverted, or you could put diverter tees in at both A and B, or you could just do something crazy and make the water go an extra few turns and feet between A and B.

Big Ed · October 2005

Vanturi tee

Use two venturi tees just to make sure......

laurence salvatore · October 2005

vacuum the convectors and pipe th dinning room one 1.25'x .5" regular tee 1.25" pipe then 1.25"x.5" monoflo on the return side of the convector. make sure the monoflo tee you buy has a cone in it not just a baffle. i have always used genuine B&G monoflo tees and not had a problem. the B&G's are also good for the novice because they have arrows to show wich way to install the tee. make the repair in copper if you are more comfortable screwing the larger pipes together, i might have a Taco tee inthe size you need left over from when gramps wouldn't let the lads solder

Problem with Monoflo system

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