I have a Weil-Mclean boiler for my heat and hot water. My showers and tap water is always warm and never hot enough. Boiler runs fine was just serviced a few months ago (oil-fired). I turned up the hot water valve right off the boiler to max. Inside the transformer box there are 3 dials. One says HI, the other LOW and the third says DIFF. The HI and LOW are both set to 160 degrees. DIFF is set at 11. The boiler pressure/temp gauge reads 200 for temp. I've insulated the hot water pipes as far as I can go. How do I get my tap water hotter?
The water should be hot enough with those settings. You have done the obvious insulation work where you can. All that I can think of is that the hot pipes are partly furred up, and restricting the hot water flow. When the hot water only is run, is it hot? Is there a good flow? If poor flow then you can only turn down the cold to get hotter water. Putting in a water softener will eventually clean out the pipes, but it is much quicker to put in new pipes where you can. Good luck!
I would bet that the temp gauge on the boiler is broken. Considering that the operating and high limit are both set at 160 deg - the boiler shouldn't get to 200. You indicate that the diff is 11 degree. This would mean that the boiler starts at 149 deg, (160-11), and shuts off at 160 deg. Depending on the temperature of your cold water and the size of the domestic heat exchanger in the boiler, you may not be getting more than a 70-80 degree rise in temp. So if your cold water is 40 deg - then your hot water will only get to 110-120 deg. What you might consider is putting in a small storage tank, (say 5-10 gal), with a recirc pump - tied into the hot water coil. The circuitry and controls are a bit much for this forum, but you can either research the net or email me for a sketch or get a heating professional to install.
Water from a warm water tank would be no longer as warm as you wish, because of the fact the producer does not desire the criminal accountability for injuries. you may turn the temp up your self. If the heating factor has no longer failed, then you certainly could evaluate this: use an equipment that makes use of warm water first. which will reason your warm water heater to warmth up back and supply you yet another tank of newly heated warm water. If no longer something occurs, then you certainly desire a clean one.
