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hot water pressure

highwyre Member Posts: 2
i have an efm oil boiler. my problem is; i seem to have lost the hot water pressure. it just trickles out. the unit is 25 years old & never had this problem before. what could it be & how can i fix it. it is hard taking a shower, doing wash & running the dishwasher. i NEED help, it's making me crazy!!


  • Alan R. Mercurio_3
    Alan R. Mercurio_3 Member Posts: 1,620
    Coil flushing

    It sounds like you have a domestic coil that is becoming blocked with minerals. This can be treated with an acid flush however I must warn you sometimes you are risking having the acid destroy the coil. You could just have a new coil installed however based on the age of the system it may not be worth the investment.
    Your friend in the industry,

    Alan R. Mercurio

  • Al Letellier_21
    Al Letellier_21 Member Posts: 402
    loss of hot water pressure

    Good advice from Alan but you didn't mention what you have for a mixing valve or if you have a flow restrictor in place. Either one of these could be the culprit as well. A certaim brand of restrictors used a rubber insert to restrict flow and these have been known to swell over time and block flow to the coil. The tempering valve may be the issue as well. Check these first as they are easier and less costly to replace. If it turns out to be the coil, follow Alan's advice...he know of what he speaks.
  • Alan R. Mercurio_3
    Alan R. Mercurio_3 Member Posts: 1,620
    Good Catch!

    Good catch, Al! I totally forgot about the tempering valve or restrictor as a possible cause. That’s why they pay you the big bucks :)

    PS. It was so nice to see you last week.
    Your friend in the industry,

    Alan R. Mercurio

  • Jean-David Beyer
    Jean-David Beyer Member Posts: 2,666
    edited May 2011
    used a rubber insert

    Swelling of rubber inserts in plumbing devices...

    I had an English pressure balancing temperature regulating 2-stage mixing valve for my darkroom when I first built it. I got pretty good at rebuilding the @#$%^& thing because a lot of the components were made of a synthetic rubber, including the "piston" that adjusted the balance between the hot and cold water. Maybe that rubber worked with the water in England, but here in New Jersey, it would swell to the point where the valve was not free to move after about 3 years, so the valve would not regulate any more. I was complaining about this at a trade show  to  this to a rep from the manufacturer of a competing valve made in USA, who said his valve would not have that problem. He disassembled one in front of me (and a bunch of other spectators) to show me what he meant.  All the moving parts were beautifully machined stainless steel. Except for one spring, the rest was brass. Except the O-rings that were synthetic rubber, one valve seat that was Teflon,  and the control knob that was plastic. I rebuilt that one just once after about 25 years.

    Part of my early learning that the cheapest thing is sometimes actually the most expensive.
This discussion has been closed.