How to bleed the floor radiant water heat

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Old 12-25-11, 05:09 PM
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How to bleed the floor radiant water heat

Hi there,
Merry Christmas.
Well, at least I got a cold feeling Christmas.
I had tried to bleed the water heating system of my house. (please refer to the diagram.)
I can bleed the air out on the 1/F water baseboard heat but could not get the floor radiant water heat done.
For the bleeding of 1/F,
1) I turn off the boiler (off the fuse at main panel of the house)
2) Shut off all thermostats of each room / zones.
3) I shut the ball valve B1, B2.
4) I open the zone valve V1 and locked it in place (say 1/F Master bedroom).
5) I turn on the release water tap R1, connected it with a hose to a bucket.
6) Water coming out as well as some bubbles.
7) Watch the pressure gauge at the boiler: I added more water through water pressure regulator PR1 so that the water pressure remain between 15 -25 psi.
8) Till all the air coming out and the release water from R1 is steady and without air.
9) Then I shut off R1. Then V1, B2 and B1 respectively.
10) Then I proceed with other room / zones on the 1/F with the same procedure with V2 of 1/F.
11) It works and the baseboard heater became warming on the 1 / F. when i restarted the boiler again.

As for the G/F, It runs with 2 control zones through different loops (as shown in the diagram).
I try to bleed it :
1) I turn off the boiler (off the fuse at main panel of the house)
2) Shut off all thermostats of each room / zones.
3) I shut the ball valve B1, B2, B3.
4) I shut off all the valve at the loops:N1 - N5, and S2 - S4.
5) I open the zone valve V4 and locked it in place (say Southern room of G/F).
6) I had tried several attempts here, will stated as step 6.1, 6.2...etc below respectively.
7) I turn on the release water tap R2, connected it with a hose to a bucket.

say: 6.1)
6.1.1 I turned only 1 valve loop open, one at a time (say S2 and no water coming out from step #7 (only a few drop of water coming out, say less than 1 litre or just less than 500 cc. - water is darken colour).
6.1.2 try the other valve loop, S3. S4 respectively. Nothing happen.
6.1.3 Try the Zone valve V3, and then N1 to N5 respectively. Still nothing happen.

The floor is still as cold as water.

6.2) Do not know why S1 do not have shut off valve, therefore, I try the following another day.
6.2.1) Shut all valve loops: S2 - S4 and N1 to N5., I open the zone valve V4 and locked it in place.
6.2.2) Then I I turn on the release water tap R2, connected it with a hose to a bucket. Just a few bubble / water coming out.
6.2.3) I wait for over 1 minutes, and nothing happen.
6.2.4) Even the water pressure gauge do not drop or raise.
I give up and get the boiler turn on.


** Later, I discovered that the G/F floor start became not so cold. After 3 hours and after 24 hours.

At the beginning (before and right after bleeding, floor temperature 7 - 11 C.

3 hours after 6.2 steps, floor temperature: 13 - 15 C

24 hours later: 16.5 - 18.5 C.
(I used a infra temperature measurer to measure the floor from 1 - 2 ft above the ground.)

My question is why I can't bleed the air and no water come out as what I did to 1/F?
How did the G/F became not so cold even I could not bleed out water?
The most important one: What is the proper procedure for bleeding the floor radiant water heat system from my house.
Any suggestion will be greatly appreciated.
Merry Christmas and Happy New Year.
Thanks.

Don't know How.

Here is a diagram for the boiler

http://docs.google.com/document/d/12...GDzeFUCdQ/edit
 

Last edited by NJT; 12-25-11 at 06:49 PM.
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Old 12-25-11, 06:31 PM
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I can see that you have done your homework very well! While your graphic drawing is not of a 'standard' form, it is quite good for understanding your system! Thank you.

First, let me talk about ball valve B2. If this is a fin-tube baseboard zone as you say, I see no need or purpose for B2. I believe that you should run the system with that valve CLOSED at all times. It appears to be a SYSTEM BYPASS valve, and for baseboard systems this is never needed.

You may wish to open this for a time when you are removing the air from the system, to get the air trapped in that section of pipe out, but leaving this valve open while you are trying to remove air from the baseboards may prevent you from doing so. Remember that the water will take the shortest path that it can, and will go through that pipe and out if it is a shorter path than through the baseboards.

Certain types of boilers DO REQUIRE this valve though, so please tell us the make and model of the boiler!

We will talk more about that later... after others look and comment about it.
 

Last edited by NJT; 12-25-11 at 07:13 PM.
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Old 12-25-11, 06:47 PM
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Next, I would like to talk about the water pressure regulator.

When one is purging air from a system, it is desirable to run a FASTER flow of water through the pipes in order to move the air ahead of the water. In order to do this, there is a feature of the pressure regulators that will allow this function.

On top of the regulator is a 'lever'. If you lift that lever the regulation of the valve will be bypassed and water can flow through at a faster rate. When you open the drain with the hose, next lift this lever to get a faster flow.

Never lift this lever when the system is closed or you will have too much pressure!
 
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Old 12-25-11, 06:54 PM
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I want to talk about the tubing in the floor next.

If this is tubing that is in a concrete floor, you must understand that it can take many hours (as you have found out!) for this floor to show any warmth after turning on the heating system. In-floor heating works on the principle of "low and slow".

The water entering the floor should not exceed 110-120°F (sorry I don't know Celsius well) so the mixing valve should be adjusted to provide this temperature water to the floor tubing.
 
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Old 12-25-11, 07:00 PM
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Finally, why can't you make water flow through the floor tubing?

I believe that the water is not flowing through the mixing valve.

Before you began this process, had the boiler been running? Was the mixing valve HOT?

If this valve was hot, it may not allow water to pass through in the direction which you were expecting it to pass through.

It is always best to allow the boiler and ALL the piping to cool to less than 100°F before beginning this type of work.

Last words in next post...
 
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Old 12-25-11, 07:09 PM
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It is rare that in-floor tubing needs to be purged of air. Since this tubing is all below the level of the boiler it is difficult to have air trapped in this tubing.

On the side of the boiler is an AIR SCOOP with the expansion tank hanging below, and on top there is a "FLOAT TYPE AUTOMATIC AIR VENT". The air scoop and the air vent are there to collect the air that is in the system and vent it to the atmosphere.

There is a small cap on the top of the air vent. This should be left LOOSE so that the air which is captured can exit the system. Make sure this cap is LOOSE.

If the cap is tight and when you open it, this vent LEAKS WATER, then you need to replace that vent.

A question for you:

Why did you feel it necessary to purge the air and flush the pipes?

Was there a problem that you are trying to correct?

In general, good advice is to NEVER add fresh water to a system once it is operating properly. There is no need to flush these pipes for maintenance. The stinky discolored water in the system is NORMAL and should be left alone.

Fresh water contains OXYGEN dissolved in the water. After the water is heated and run through the system, this oxygen leaves the water.

There are THREE things which need to be present for corrosion of ferrous materials to occur.

1. Ferrous materials.

2. Water

3. OXYGEN

If you take away any ONE of these items, corrosion can not occur. You can't take away the Ferrous or the Water, but you CAN take away the Oxygen.

In short, every time you add fresh water to a system, you are causing corrosion.

So please explain what the reason is for wanting to do this work.
 
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Old 12-25-11, 08:37 PM
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Thanks for you quick response.
I do not really know the function of the ball valve B2. (Consider it is a clock, the copper pipe is at 9 & 3 direction / ie: horizontally, ) and the ball valve B2 is pointing at “4” all the time (I think that is an open direction). It can only turn to “6”. I supposed that will shut off the pipe of that section. That why I shut this (at “6”) when I try to bleed the 1/F. As you mentioned, if this open, the water will go through the shorter rout through this B2 to R1.
I think shutting B1 is to avoid new water coming from bump 1 then through B1 to R1. And shutting B2 is to force the water to go through V1 to 1/F and returned through the return pipe and get out through R1 tap. Then I can get the air out from 1/F V1 zone area.

The boiler is: Mini-gas Energy Efficient Gas Boiler model MG100



2) Yes, For the water pressure regulator PR1, I open it “at interval” to maintain the water pressure (constant flow) when bleeding. I had not open it all the time because I am not sure if I open it while bleeding, the 30 psi release valve (before the expansion tank) will open or not.


3) Yes, It is laminate floor and tile on concrete floor at the G/F. The thermostat shown in the diagram I belief that state the water temperature going to the G/F after the mixing valve M1 and through pump 2 is about 100F (or around 106F max. 40C) .


4) I had not mentioned that the mix valve is of brand Sparco, Warwick, USA with right hand side marked – 110F (not sure) & Model M102 (not sure as the label was torn)
It had 4 setting, and it was at “4” before I did anything to the system. I did turn it a bit to “3” (I turn it clockwise) after my 1st attempt in bleeding the G/F system.
The air scoop is not cap. (Should I cap it loosely? I did found the cap –like the cap of the tire except with a small hole at the upper sideway.
And I did hit the expansion tank and the sound seems normal – The upper part is solid while the lower part is a hollow.
The boiler is running before I did the bleeding. I bleed the system because, the G/F is cold and I hear hammering sound at the 1/F. (It was served 1 year ago. We feel the G/F were cold before we moved in this house. The technician come and did “something”. We don’t know what he had done as that was conducted through the previous owner. According to the parts he left behind and the “new burn” at the pipe, it is some zone valve, Taco water pump replacement cartridge, presuure release valve...etc). We can feel the G/F corridor tile floor warm at that time. No sure when it got cold. I believed very soon after the services. (maybe a month or so.). We just don’t know the system and don’t have time at that time (moving, then it was summer.) It was not until recently, the hammer sound became louder and more frequently that I think it is better to take care of it, once and for all.

Just do not know how to do it properly.
Thanks a lot.
 

Last edited by don'tknowhow; 12-25-11 at 10:08 PM. Reason: typo
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Old 12-30-11, 09:45 PM
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[editor note: this post was moved from another thread to back here where it belongs]

Hi there,
I had similar / or half that problem. (ie: the lower psi is at 10 psi or even lowest as 8 or 9 psi). Yet when boiling, it will raise gradually to around 20 psi (just before the burner was cut off at 170F). Have not noticed the pressure before or have not taken record of that before (I should take notice before I did anything to it, but I haven't take record of that). It is a few days after I had tried to bleed the system and then I noticed that the psi drop gradually to a point that it reads at the lowest 8psi (mostly just below 10 psi).
Long story short '/ brief details:
1) right after the bleeding, it was at just below 20psi (or just 20psi) before I restart the burner.
2) Then the burn started and the psi raised gradually to close to 30 psi. (I would say at some time, it exceeds the 30 psi, say 31 or 32psi, but I did not hear the pressure release valve take any action). -----------Any idea why? faulty pressure release valve or temperature gauge?
3) After several burning cycles, I would say around or over 10 cycles, the maximum psi just before the burning was cut off (at around 170F) is reduce to around 25 psi and gradually stable at 20+ psi. And the kick in burning (at around 155F) is around 12 psi ----- of which I though was normal and stable.
4) Then after a few days, i noticed that the lowest psi had gradually drop down to below 10 psi (the lowest is 8 psi).------------------- Is there a leak? Or the water pressure regulator did not work properly?
5) This time, I try to measure the timing and the psi and temperature:
Kick in burning at 155 F around 10 psi and stop burning at 20 psi at 170F. Burning time is around 1 mins. While the pending time till the next kick in is around 3 mins. (Count that for 11 cycles, and the readings are quite identical. ---------------Is the burning time, and kick in frequent normal? To me, it looks like quite frequent as on and off within 1 and 3 mins.-----------Any thought?

Not sure if "8 psi" is still an "acceptable" normal operating psi.

Hi NJ Trooper: Any suggestion and supplementary thought on my last thread on "How to bleed the floor radiant water heat ?" http://www.doityourself.com/forum/bo...#ixzz1i5NplrHT ---- much appreciated. Thanks.


Thank you all.



Don't Know How.
 

Last edited by NJT; 01-01-12 at 05:33 PM.
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Old 01-01-12, 02:04 PM
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Hi NJ,
Thanks for your previous responses.
Any other suggestion about my recent reply to you about the details of the system and the boiler.

Now, I am getting a lowest 5 psi reading (mostly at 10 or just below 10 psi) before the boiler start to burn. (The psi bedfore the burner stop is mostly at 20 psi, but sometime come close to 30 psi) Is that normal? Or what causing that?

Any idea or suggestion is muich appreciated.
Thanks.


Don't Know How.
 
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Old 01-01-12, 02:47 PM
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It sounds like your expansion tank is kaput. If it is a bladder type (looks like a propane tank), it needs to be replaced. After you replace the expansion tank, refill the system to a minimum of 12 psi when cold. Your low pressure is most likely the cause of your no heat situation. Make this fix ASAP.
 
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Old 01-01-12, 05:14 PM
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Hi drooplug,
Thanks for the input.
Actually, I had warm temp at 1/F zones before & after bleeding, Cold on G/F before bleeding attempt and just get around OK temp at the G/F after "bleeding attempt" (before attempt bleeding, G/F is range from 43F - 52F; then I got quite stable 61F to 67F after bleeding attempt. However, I could not get warm feel (or at least normal feel) on tile and laminate floor with bare feet as 1 year before.

Since I could not bleed the air from the G/F radiant heat system, but it did warm up a bit after my attempt. (As this thread #1 & #6 stated with diagram attached). Would it be possible that "some water" could enter into the G/F floor now and that expand of route / volumn could cause the psi to drop gradually?

How about the water presure regulation "PR1". Will it be retiring too? Or will it be easy to replace the expansion tank to check the result first.

For details of the temperature, boiling time interval and the psi changes recorded were on:

Read more: [editor note: the referenced post was included into this thread, see message #8. It is no longer in the other thread]

Thanks.

Don't Know How.
 

Last edited by NJT; 01-01-12 at 05:36 PM.
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Old 01-01-12, 05:47 PM
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I'm not sure what you are saying or asking, but your expansion tank should be replaced and your system should be pressurized to 12 psi while cold. The pressure will increase when the water is heated.
 
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Old 01-02-12, 09:27 AM
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Hi Drooplug,

I will try the expansion tank first.
Thanks.



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