Heating boiler water feeder valve clogged strainer replacement.

This article series illustrates how to diagnoes and fix hot water boiler (hydronic heat) pressure reducing valves and types of manual and automatic water feeder valves used on hot water heating boilers, including when and how to add makeup water to a boiler.

Hydronic (hot water) Heating Boiler Pressure Reducer Valve Repair

Here we illustrate the replacement of a clogged strainer in the bottom of an older B&G B-8 pressure reducing valve.

We found this valve on a hot water heating system in a Two Harbors Minnesota home built in the 1960s.

This was an original pressure reducer that had served more-or-less for over fifty years.

[Click to enlarge any image]

Removing the Pressure Reducer Strainer Nut

On a typical B&G pressure reducing valve (aka "water feeder" to the dismay of the manufactuer) there is a strainer in the bottom of the valve. To remove it one needs to remove the strainer nut.

It was plain hell just trying to remove the pressure-reducer strainer retaining nut on this 50-year old valve.

Using an adjustable wrench, as carried by most service techs, is going to give a too-short wrench handle, not enough torque, and you'll probably round off the nut facets.

I used a longer 1 1/4" box wrench. In my photo above I've flipped over the wrench to connect the open-end to the strainer nut so that you can see the size markings. But using the closed-end of a box wrench is most-secure.

With the nut removed you can see the strainer inside the pressure reducer valve. Along with rust and crud.

I also had a devil of a time getting this clogged old strainer out of the valve - shown in more detail below.

Later when I disassembled the entire pressure reducer I also found that the valve inside the pressure reducer was frozen solid.

Even replacing the strainer wouldn't have fixed this valve.

Details of the jammed water valve in the pressure reducer are shown in this separate article:

PRESSURE REDUCING VALVE DISASSEMBLY - not something that I recommend.

Just below we show the location of the pressure reducer strainer and the steps in replacing it.

Unlike complete disassembly, strainer cleaning or replacement is a recommended service procedure for pressure reducing valves on boilers.

Steps in Replacing or Cleaning a Clogged Pressure Reducer Strainer

Photo: a very clogged strainer in a B&G B-8 pressure reducing valve.

[Click to enlarge any image]

How to Check for a clogged strainer in the Pressure Reducer/Feeder Valve

If the pressure reducer will not feed enough water into the boiler to reach the desired cold-pressure setting, before messing with re-adjusting the valve's feed pressure nut and screw, consider that the internal strainer in the valve may have become clogged.

1. Turn off the cold water supply valve at the inlet side of the pressure reducing valve
2. Turn off the heating boiler - set the electrical service switch to OFF to shut down the entire system.
3. Remove all pressure and temperature from the heating system to allow safe work on the pressure reducing valve
   
   Watch out: water in the heating boiler may be at dangerous high pressure or high temperature.
   
   Before proceeding to work on the pressure reducer valve you must either reduce the heating system internal water pressure to zero, OR you must isolate the pressure reducing valve from the rest of the the heating system.
   
   Leave the system drain valve open and allow the heating system to cool to a safe temperature - below 100 °F. Otherwise you risk serious injury or death or property damage.
4. Loosen and remove the strainer nut located on the bottom of the pressure reducing valve

5. Remove and clean or replace the strainer found in that opening

It was impossible to get the strainer out of the pressure reducer without destroying it.

I had to pry it out with a screwdriver and pliers. In my photo above you can see the side of the strainer is a bit bent.

Also as I show below, the strainer was badly clogged with scale and rust. I could have perhaps cleaned it by soaking it in vinegar.

But best would be to install a new strainer.

That's why B&G's PRESSURE REDUCER REPAIR KIT (described below) includes a new strainer and O-ring.

6. Reinstall the strainer and nut with its O-ring (don't lose or damage the O-ring or the valve will leak) and tighten the nut to at least 10 inch-pounds of torque, and not more than 100 inch-pounds of torque.
   
   Watch out: don't use Teflon tape when installing the pressure reducer strainer nut and o-ring or the risk is that you will over-tighten and damage the equipment making it and the system unsafe, risking injury or damage.
7. Close the heating boiler drain and re-fill the heating system with cold water.
8. Vent any excess air from the heating system - as you may have introduced air during the drain and refill procedure. Remember to close the bypass valve or fill valve when the heating system has been filled to its cold starting pressure.
9. Check the system for water leaks, especially where you have been working and disturbing parts
10. Turn the boiler electrical service switch back on, make sure the room thermostat is calling for heat, allow the heating system to resume normal operation.
11. Check a last time for leaks.

Watch out: The manufacturers of this type of automagic water feed valve recommend that additional manual control valves be included in the piping system, so in some installations you might also find that the automatic water feeder is not really so automatic.

... the manufacturer warns that the purpose of the pressure-reducing (and automagic water feeding) valve is to fill heating boilers after installation or servicing. The company says

"It is not a safety device and is not intended to be used as as a water feed valve to control boiler water at a safe operating level".

Complete Disassembly of a B&G Pressure Reducer

This information has moved

to PRESSURE REDUCING VALVE DISASSEMBLY

How to Use the Pressure Reducer Valve Repair Parts Kit

B&G provides a repair parts kit for this valve.

• To use the pressure reducer valve repair kit you will need to shut down the heating system, drain it, cool it, as we described just above at the strainer cleanout procedure. Then
• Remove the valve body cover using a #25 Torx screwdriver that fits the screws around the valve body;
  
  (Older pressure reducing valves use ordinary slotted-head screws like those shown in the article above.)
  
  B&G points out that you can use 1 /8" Allen wrench instead of a #25 Torx driver in an emergency but we can confirm that you will probably strip and damage the screws, just as a Harley Dealer's mechanic did to my Road King (another argument for doing your own work).
• Remove the valve spring cap and spring you'll find inside
• Remove the hex nut (this is the lock nut that holds the screw stem in place) by holding the stem assembly stationary while turning the nut counterclockwise. B&G warn that the stem may drop when you remove the hex nut.
• Lift off the spring plate, diaphragm, and valve plate - I'd inspect all of these parts and the others listed below for damage
• Pull the rubber check valve from the valve body and replace this part
• Insert the new valve stem assembly (that came in your repair kit) into the valve body through the strainer opening in the housing, and hold it in place. [A helper may be handy here]
• Place the new valve plate, knob side down, on the stem assembly
• Set the new diaphragm on top of the valve stem, aligning the holes in the rubbery diaphragm material with the screw holes in the valve body - you want the reassembly screws to line up with these holes - otherwise the diaphragm may end up cut or twisted and you'll have ruined the job
• Place the spring plate over the diaphragm on top of the stem assembly
• Thread the hex nut onto the valve stem assembly. A dab of Loctite (thread fastener) must be added to the hex nut before threading it onto the stem.
  
  Watch out: don't use more than a tiny dab of Loctite or you will seize the valve, making it inoperative and the system potentially dangerous
• Place the spring, cap and body on top of the valve
• Align the valve body cover holes with those in the body (you got that diaphragm straight, right?) and fasten those stripped (or replaced) Torx T-25 screws into the body
• Reinstall the strainer nut (the strainer is in place, too, right?) with its O-ring into the reducing valve body bottom and tighten it to at least 10 inch pounds and not more than 100 inch pounds.
  
  Watch out: see our warning above about watching for a damaged O-ring (replace it) and about not using Teflon tape on this part, at risk of over tightening
• Close the boiler drain and refill and vent air from the heating system with cold water as we described above. Remember to close the cold water bypass valve or fill valve.
• Check for leaks
• Turn the heating system on, st the thermostat to call for heat if necessary, let the system reheat,
• Check again for leaks
• Check the system operating pressures cold, and hot

Pressure Reducer & Flow Control Valve Manuals

• B&G Flo-Control Valves - installation, operation, and service instructions manual [PDF] original source Bell & Gossett, 8200 N. Austin Ave., Morton Grove IL 60053, USA - Tel 847 966-3700 Fax 847 965-8379 . www.bellgossett.com/BG-Literature-Detail.asp?LiteratureID=607
• B&G / ITT Reducing Valves, Instruction Manual V55999: Reducing Valves Installation, Operation, & Service Instructions [PDF] Bell & Gossett Air Separators and other heating system components, Bell & Gossett, 8200 N. Austin Ave., Morton Grove IL 60053, USA - Tel 847 966-3700 Fax 847 965-8379. Original source www.bellgossett.com/literature/files/610.pdf

...

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