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Joined on September 1, 2010

Last Post on September 16, 2014

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Old Tank

@ September 16, 2014 1:28 PM in Need help with old hot water system

There are several variations on those old tanks: some have special drain fittings, others don't. You could indeed connect it to a SpiroVent on the return as long as the pump is down stream of it. It would still be pumping away from the PONPC.

The water isn't quite as hot there as on the return, so the air is not released from the water as it would be on the supply, but it will still work. But again, most of your entrained air is going to the top of your rads.

If you choose a diaphragm tank, make sure it's properly sized. A Extrol 30 is usually undersized for an old system with large pipes and c.i. rads.

Air elimination

@ September 16, 2014 12:37 PM in Need help with old hot water system

The old xtank was also your air elimination device. You don't want to install a diaphragm tank unless an air separator is also installed. Since the entire system flow MUST go through the MBR (micro bubble resorber, air separator) your gonna have some major re-piping. In that case, I would move the circ to the supply downstream of the MBR.

If you simply re-connect an open xtank, I'd leave the circ alone unless there were air issues at the upper part of the system.

What kind of emitters do you have? If they are c.i. rads, then you'll still have to manually bleed them even with an MBR.


@ September 15, 2014 1:04 PM in Old House, Single-pipe hydronic with diverter tees

Here's a link to info on it from right here on HeatingHelp:

24v stat...

@ September 15, 2014 12:52 PM in What is a 24V Thermostat

That means it operates on 24v system. The stat doesn't produce any power, the transformer does that.

There are numerous ways the system can be wired depending upon the components used and the control setup.

Given the nature of your question, it's obvious you're attempting something well beyond your knowledge and expertise. Please, call a pro who knows control work before you fry something expensive or cause a fire or safety issue. This is NOT something that someone will be able to talk you through.


@ September 15, 2014 12:33 PM in Converted 2 pipe steam to hot water

Raise the pressure.

Water temp

@ September 15, 2014 9:58 AM in Converted 2 pipe steam to hot water

Raising the water temp will cause it to release entrained air into the top of the rads. You want to purge with cold, but set the system hot.

Don't expect an air separator in the basement to remove the air that's in the rads. You need to manually bleed it from the top of each rad. The columns in the rads operate on gravity and the velocity in them is too slow to carry air back down to the return.

The soap (Dawn) is a good idea, but it only helps where there's forced flow - in the the piping - not the columns of the rads.

Personally, in think the choice of a monoflo with c.i. rads was the worst one, but what's done is done.

Did you follow the guidelines for monoflo piping? You can find them on site.

Where in N. Va?

@ September 13, 2014 11:48 AM in Offer: Burnham MPO IQ84

Can you post a pic of it?

Maintaining System Pressure

@ September 13, 2014 10:58 AM in Maintaining System Pressure

I found this photo over at I'm not sure but it appears that someone rigged a bug sprayer to pressurize the hydronic system.


@ September 12, 2014 9:52 AM in Is this correct?

They're trying to keep condensate that forms in the flue from running back into the boiler. Buderus does this too and supplies the Tee with the boiler.

If you have a very short flue run, such as the boiler back to back to the flue on an outside wall, then you don't need it, but the manufacturer may still require it.


@ September 11, 2014 3:33 PM in AC help

That AHU is listed for R22 and comes with a R22 TXV.

Attempting to connect an R22 coil (even if the TXV is changed) is a bad idea. It's almost impossible to flush all the mineral oil from the coil and that will result in reduced performance and equipment life.

That will happen even if it's a listed ARI match. What you got will not be and therefore will carry no warranty.

There's no shortcut to doing it right, but that will result in the best performance and least cost overall.

If you're a homeowner attempting this, I highly suggest that you get a QUALIFIED pro and save yourself a lot of stress on your person and wallet. No competent pro would attempted this.

Point Of No Pressure Change

@ September 9, 2014 8:38 AM in confused?? or is this correct too?

The PONPC is where the internal expansion tank connects to the primary loop inside the boiler. The secondary (house) loop "sees" the entire primary loop as the PONPC. It is the PONPC that the circ should "pump away" from. The air and dirt separators are not the PONPC; the connection point of the expansion tank is.

This can become confusing because we typically connect the xtank to the bottom of the air separator, but it's that connection that's the PONPC, not the air separator itself.

You shouldn't need the external xtank unless the volume of the internal tank is insufficient. In that case, I would recommend that you either connect the extra xtank to the same point as the internal one or disconnect the internal one which would make the house loop the primary. You don't want two PONPCs.

For clarity: it's my understanding that the primary loop is the one where the xtank is connected and has the PONPC there.

Siggy explains it this way in his book too, but some in the industry identify the primary as the boiler loop. This makes it confusing sometimes.

Flow Rate

@ September 8, 2014 9:09 AM in Gravity hot water diverting tee

The flow rate will vary depending upon the water temp. As it gets hotter, it will increase.

If you measure the Delta T between supply and return, and you also know the btu output of the boiler, then you can use the universal hydronic formula to find the gpm.


@ September 7, 2014 2:10 PM in Gravity hot water diverting tee

If using a cast iron boiler which has little or no head. But a mod/con which usually has high head and needs high velocity is gonna need hydraulic separation to work with this type of system.

Remember, it's not just a gravity system; it's a system that requires stratification in the piping to function.

Like Button

@ September 6, 2014 11:06 PM in PVC Venting on boilers again!

We need a "Like" button on here similar to what FB has.

Bob Boan likes Tony's comment.

Eureka Tee

@ September 6, 2014 10:26 PM in Gravity hot water diverting tee

It's a Eureka Tee.

There's a thread on the wall a couple of notches down that's discussing this titled : Old house, diverter Tees.

JStars advice about using a buffer tank is good. It's the best solution that we came up with, too.

Large Q Tips

@ September 5, 2014 6:42 PM in Mini-split achilles heel

I installed one in the office of my diesel mechanic. Even though he keeps the doors shut that connect to the shop, there's a lot of nasty stuff that gets into the mini.

I showed him how to get to everything and he uses some of the super-long (12 inch?) Q tips to clean the blades of the blower wheel. Any mild cleaner will be okay on the coil.

The manufacturers really need to come up with better filtering for these. My only reall complaint.


@ September 4, 2014 11:25 AM in Old House, Single-pipe hydronic with diverter tees

If that IS some form of a Eureka fitting, then the warmer water would flow out of the top to the branch circuit and return the cooler water at a lower point on the side. That is, under gravity flow.

The wye seems to be what's confusing, but it's only aiding the return flow into the Eureka fitting.

Again, think in terms of gravity flow with warmer and cooler water in stratification within the pipe. That's the only way that kind of fitting could work. That's why pumping the system defeats its purpose.


@ September 3, 2014 8:04 AM in Old House, Single-pipe hydronic with diverter tees

I've never seen one (even in a book) that was wyed like that one.

The presence of circulators, which were obviously added later, makes me wonder if it is the eureka fitting. It seems to me that they would not interact well with that type of system. Your thoughts?

Better pics?

@ September 2, 2014 9:24 AM in Old House, Single-pipe hydronic with diverter tees

Icesailor has over fifty years experience in this trade and I have over forty, but neither of us knows what a "four way" Tee is. Your pic is indicating some form of wye fitting but it's not at a good angle. Could you get a better pic perpendicular (side) angle?

Also some pics of the diverter Tees in the system?

I can see there are multiple leaks on the system. They will be the death of your boiler if not corrected. You should give immediate attention to them.

Tech Bulliten

@ September 1, 2014 2:52 PM in major problems with new carrier system

I just got a tech Bulliten from Emmerson acknowledging the sticky substance but saying they had not ID'd the cause and they were working with all manufacturers to find it. They acknowledged that it was industry wide and not limited to one manufacturer. I don't see how Carrier's bulliten lines up with that.

Wall Mounting

@ September 1, 2014 10:08 AM in EDR For Radiant Radiator

The brackets came with the rad.

I would check with a Myson distributor and have them order a set. There also may be a floor mount kit available that would hold it up off the floor so air could be drawn into it.

Panel Rad

@ August 31, 2014 10:08 PM in EDR For Radiant Radiator

It would get a lot more btu output if it was mounted on the wall like it's supposed to be so air could enter thru the bottom.
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