air lock in water heater!

Sounds like the filter is not fitted correctly, does it have flexible hoses? If so an over tighened jubilee clip could be the problem.

Good luck

The hot water supply pipe must logically come from the top of the tank  (hot water rises) with the cold supply entering at the bottom,   thus any air would escape, forced out by the hot water rising.

How many showers one might get from a 100 litre tank would depend on the max heat the thermostat is set at,  from tepid to as hot as possible,  and also the temperature of the water you prefer for the showers.  I have solar heating for the water, on less sunny days I can have little or no hot water in the tank and thus I use the emersion heater, but set to a low temp, thus get maybe just one tepid shower

Also changing the tap as you say would not empty the tank, as the hot water is supplied by the pressure of the cold water entering the tank.  Thus you turn off the cold water to the tank, and so, one would not expect any hot water to be lost.

Curious

A stirrup pump on a fully open hot tap might just work.

The thermostat is plastic , probably black and has an adjustment to turn it to hotter or colder.  If you turn it slowly you can hear when it clicks on or off.

If you want to replace, switch off the power, note  which cable goes where, disconnect, hold the thermostat and pull it out.  

 You can test it in say a kettle or saucepan to see if it clicks on and off when you put it into hot water.

Get yourself a plumber before you start messing about with Air locks...Water tanks...Boilers...Dipping Electrical items in water.

Could be a whole lot cheaper then blowing yourself up or busting something expensive that had nothing to do with your immediate problem in hand.

Quesada as you have changed the mixer taps, I would think that you are quite capable of changing a thermostat.

I have always been into DIY, doing a wide variety of work.  One of the first was installing a solid fuel boiler and a central heating system, including the hot water supply.   

 For about 5 years when I came to Spain,  I was a 'handyman'  doing all sorts of maintenance work in apartments and villas. I took care of problems for a couple of agencies which did holiday rentals, so repaired lots of things damaged by not too careful holidaymakers. 

 I have adjusted and replaced quite a few thermostats and It really is not rocket science.   The mixer tap job you did requires more expertise. 

But employ a plumber if want. If everyone did it themselves I would not have had the 5 well paid work that did, and for that matter not so many friends now who are always calling on me to fix this and that.  I was repairing a persiana, fitting a smoke alarm and replacing the rollers on some sliding doors,  this morning: 

As they say:  A friend in need, is a pest !

So there you go Quesada11 you have now had an answer to everything you didn't need to know except how to fix your problem of what you consider to be air in your pipes.

Just because you undone one nut on a flexi water pipe, one nut on a tap thread, reversed the process, ended up having no hot water which presumably you did have before, is it at all possible you have some other underlining problem with your system, could it not be just a coincidence this arose after you changed your taps, like I said get yourself a plumber, someone that knows what they are talking about.

Quesada,  'Get a plumber'  is really good advice for everyone who thinks testing a disconnected thermostat amounts to "Dipping Electrical items in water" or that changing one is more complicated than changing a mixer tap. 

Although as a thermostat is electrical equipment,  maybe getting an electrician might be more appropriate.

Well, considering that the poster never mentioned what type of hot water system they have, Gas, Electric, Solid fuel etc, it beggars belief that good and correct advice can be given on an unknown system without first hand knowledge of seeing it. 

And as the supposedly thermostat mentioned seemed to have an electrical wire attached to it, so once it was dipped into hot /cold water, and if water managed to get into any electrical contacts of the thermostat, and if it tested all okay, or what to the inexperienced person it seemed to, plenty of them about, and then the owner wired it back up and switched it on...Well as we all know water and electric do mix well.

Maybe if in doubt throw the old thermostat away and get a new one, or better still get a plumber in.

It's a elecric heater I presume. You probably have a leak in the hot water system in the pipe going away from the heater. This will give you the impression of not having enough hot water as it is draining away and air can also be drawn into the system via the leak. A friend had this problem and your symptoms, it took a lot time to find the problem.

With the hot taps turned off, wait 30 minutes then hold the hot outlet pipe from the heater, it will cold if no leak and hot if you have one.

If you have a leak, call a Spanish plumber, they know where to look.

Good luck

Baz,

A Thermostat works on changes in temperature, either the air in a room or water in a hot water system,. 

 Mechanical ones use a gas or bimetallic strip.   The change in temp  either opens or closes a contact, which is just like a light switch,  so it’s either on or off.   Just like the light, if it is on, it allows power to flow and the bulb comes on, or the heating element comes on.

If the, disconnected from the electric,  unit is removed, and it is not broken, then the shaft immersed in hot water the contacts will open or close(swtiching it on or off) making a clicking sound.  That function  does not need any power, as I said it’s function, to detect the heat changes,  does not rely on electricity.  Just as a light switch will work, switch on and off, without it being connected to an electricity supply.

If you ask one of your mechanics at your MOT station how one tests a bellows type car thermostat he will explain.  The principle of the stat is the same (other than that a liquid is used in a car stat).  When it is immersed in hot water the bellows open.    In a car as the collant heats up, the bellows open allowing the coolant to flow through the block.

And as I said, it is not a plumber who installs emersion heaters but an electrician, just as the plumber does not connect gas to a system,  it’s a gas qualified engineer.

But come on Baz,  I know you are a knowledgeable guy and I suspect you are just pretending not to know about this.to wind me up !

But you don't know what type of stat it is, or heating system for that matter, and if you dip the end of a long stat into hot water only the end reading is made which is at the lower bottom of the hot water tank, which also wont do any good because the warm water is only up at the top, hence the posters no hot water.

Should the stat be one of those connected onto the outside of the tank then dipping this into hot water could introduce water into the electrical points of the stat.

I said maybe another problem was present with the system before the taps were changed because you really do have to make a mess of things and have no hot water just by changing taps over.

Never tell anyone to mess about with anything to do with water and electricity with 230 plus volts. And if you did manage to mess up a tap change then in no way go further and mess with 230 volts.

I know exactly how a cars thermostat works, and this has no electrical power attached to it, 12 volts, not directly if you want to be picky. 

My work shops are fixing DIY bodge up's done by "Fred in the shed" types pretty much on a monthly basis, I recently sacked one mechanic after a month who knew everything about everything...Even up to the point of nearly killing one of my other guys.

Almost seen and heard every bleeding expert on everything there is to see.

quesada

I was thinking along the lines of Mr Kevin   (although air getting into a pressurised system, even just mains pressure,  would seem implausible).

 Pretty unlikely as you would probably have noticed, but moving  old pipework when fitting the mixer, could have loosened an old joint further along the supply pipe resulting in a leak.  That would deplete the amount of hot water you have in the hot tank, although the thermostat would be switching back on and reheating it. 

That would account for the problem only occurring after you changed the tap.

As I said, changing the mixer probably requires at least as much skill as checking/changing the Stat.

 and if you dip the end of a long stat into hot water only the end reading is made which is at the lower bottom of the hot water tank, which also wont do any good because the warm water is only up at the top, hence the posters no hot water.
 

I am sure you know Baz that the Stat reacts to the temperature of the water at end of the stat tube.   So the dipping it in hot water test is always effective.

And thanks for agreeing, as I posted, that all mechanical stats, like the one in the car cooling system,  do not require electricity to work.

And thanks for agreeing, as I posted, that all mechanical stats, like the one in the car cooling system,  do not require electricity to work.

You mentioned that did you? Dream on.

You mentioned that did you? Dream on.

In your rush to find fault with whatever I post,   you really should not neglect to read what I say ; 

From my post  04 Mar 2015 09:11      “That function  does not need any power, as I said, it’s function to detect the heat changes,  does not rely on electricity.”

By the way, glad to hear you sacked an incompetent mechanic.  The first and last time I entrusted a vehicle to a garage for any repair was when I was 17 and they really screwed me.    Since then I have always fixed anything needed myself to ensure it was done correctly.   However, on one car with the obligatory first service to maintain the guarantee,  I stuck a piece of tape from the rocker box to the block, so I could see if they tightened down the head. When I collected it, I asked if they had, as required by the manufacture's instructions,  tightened the head. Yes of course they had.  I ask them why they had 'replaced the tape."  Replaced the what?  I then showed them the tape still in place. 

I got some compensation  and an undertaking that although I would do all the services, to ensure they were done correctly, the guarantee would still be valid.

Professionals  !!!

I am afraid no one needs to rush to find fault in your posts they are blatantly obvious, you pulled me up on a car thermostat NOT the home water heater one, read your own posts carefully.

Yes, I have had many people come into my workshops just like you, dob of paint here, piece of tape, even over-tighten wheel nuts in the hope my guys make a mention of this. Just a few of the things we get to see regular.

And if you're trying to convince me that with the modern car you can service everything yourself then all I can add to that is I have wasted over £100,000 on specialist tools for the modern motor car, but of course I expect with your vast knowledge of just about everything you could make these tools as and when needed. 

Without fail it's a godsend that we have punters (although we have a completely different name for these people) like you, it keeps us on our toes and brings to the fore as to what idiots are let out in the real world driving badly maintained cars.

Anyway enough said....Get a plumber to correctly fix your problem