Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

Replacement for a Honeywell V55155A 1100 Modusnap?

The thermostatic modulation gas control valve on my old AO Smith boiler is leaking gas in 2 locations. Rather that attempt a repair, I'd like to replace it. Problem is Honeywell stopped production of the V55155 line in 2000. There are a few 1110's on Ebay for $160 but non-returnable with no warranty. My boiler contractor will install one he has for $320 part + labor warranted. Does anyone know if there is a functional equivalent replacement available new?


  • Tim McElwain
    Tim McElwain Member Posts: 4,608
    Is that more likely a V5155A? A picture of the manifold would help so I can see how it is being used. It may be able to be replaced by a combination gas valve.
  • Yes, it is a V5155A as indicated in the thread title. It's been removed. It was in the gas supply line just before the burner.
  • Tim McElwain
    Tim McElwain Member Posts: 4,608
    Was it after a gas valve or a regulator?
  • Scott_Mountain_View_CA
    Scott_Mountain_View_CA Member Posts: 202
    edited August 2015
    Yes. See pics. My finger is pointing to the location of the V5155A before it was removed.

  • Tim McElwain
    Tim McElwain Member Posts: 4,608
    You can run it like that you will not have the modulation. What was the capillary bulb attached to as that obviously controls the modulation? It is usually sensing some feed or return piping temperature depending on what the manufacturer was looking to accomplish. With out it you will lose some of the efficiency but you could install an Outdoor Reset Control and work off a 140 degree boiler temperature. What that does it will allow the circulator only to run as long as boiler water is above 140, if it drops below then the burner will kick on. Not quite the same as the V5155A but it will help with the efficiency.
  • Thanks Tim. The capillary bulb is still attached to what appears to be an air separator mounted below the expansion tank.

    I'd like to replace it, surely this function is not obsolete? I'm not sure where to look. The boiler contractor that removed the leaking modulator said that he still has new ones in boxes and will install it for $320 part + $150-@200 labor. I've found supposedly new ones on EBA selling for $160 in the box, but I'd be concerned they were reclaimed.
  • Tim McElwain
    Tim McElwain Member Posts: 4,608
    I can't help you with the pricing that is your choice. The problem with these old controls is they get harder and harder to find. What is your location in the country? It sounds like the control is modulating off supply water temp going out a picture of the capillary bulb location would help.
  • I'm in Mountain View, CA...15 miles north of San Jose. Mediterranean climate, 39 degree design day. Impossible angle for a pic, but 100% certain capillary is measuring supply out.

    Are you aware of a current modulating gas control valve that could be installed in place of an old 5155A 1110 replacement? My boiler guy has a new one in the box, but it's 15-20 years old (he stocked up before Honeywell obsoleted it, smart move)....I'd be concerned about the condition of the gasket that separates the 2 valve halves....that's where my unit failed.

  • Tim McElwain
    Tim McElwain Member Posts: 4,608
    There is no direct replacement for that control. I would say if it has not been subjected to gas flow and remained in the box it should be okay. I am going to check a local supply house (they have more old stuff than any one I know) and see if they have them and what the cost would be. If it is worth it I could ship it to you or have them ship it.
  • Tim McElwain
    Tim McElwain Member Posts: 4,608
    My local folks do not have any. I would look to the contractor that way if it fails he will hopefully make good on it.
  • Thanks Tim, I think that's good advice. He's a neighbor, I've known him for years he'll do what's right. Thanks for spending time researching this on my behalf :)
  • ControlsRMe
    ControlsRMe Member Posts: 1
    I'm an old Boiler guy from S.F. I have baseboard heat with an old AO Smith Boiler and the same Honeywell V5155A Modusnap Gas Valve that Scott had. System is efficient and works great.
    My son lives up the bay from you in Hayward. He has the same setup as me. Unfortunately, his Modusnap Valve died and since then his gas bills have been thru the roof.
    Do you know someone who has a Honeywell V5155A Modusnap Gas Valve? The ones on EBAY are now through the roof in price. If not, do you have any suggestions? All I can find are European Combination Valves that are not legal in U.S.