Microbore for radiators

[bizzard]

I tend to collect it over night here when the air space is clear of stinky planes from Stansted airport which fly over here during the day at about 1500ft polluting everything with tons of exhaust, we can smell it.

[rusty69]

6 minutes ago, bizzard said:

I tend to collect it over night here when the air space is clear of stinky planes from Stansted airport which fly over here during the day at about 1500ft polluting everything with tons of exhaust, we can smell it.

I've not heard of using rainwater for battery top up, but thinking about it, it should be ideal if its collected from acid rain

 

 

[bizzard]

3 minutes ago, rusty69 said:

I've not heard of using rainwater for battery top up, but thinking about it, it should be ideal if its collected from acid rain

 

 

Or pop a Spangle acid drop from the sweet shop into each cell.

[rusty69]

1 minute ago, bizzard said:

Or pop a Spangle acid drop from the sweet shop into each cell.

Spangles.....a name from the distant past

[cereal tiller]

31 minutes ago, bizzard said:

I tend to collect it over night here when the air space is clear of stinky planes from Stansted airport which fly over here during the day at about 1500ft polluting everything with tons of exhaust, we can smell it.

Yeh.It's a good thing that they are Banning those Diesel Planes!

[WotEver]

16 minutes ago, rusty69 said:

Spangles.....a name from the distant past

Me dad’s favourite sweet. Always had a packet in his pocket. Hmm... I guess that made them a pocket packet. 

[rusty69]

1 minute ago, WotEver said:

Me dad’s favourite sweet. Always had a packet in his pocket. Hmm... I guess that made them a pocket packet. 

I remember the name spangles, but not the taste.

[WotEver]

Just now, rusty69 said:

I remember the name spangles, but not the taste.

As I recall they were just boiled sweets. But square. 

[Flyboy]

33 minutes ago, rusty69 said:

I've not heard of using rainwater for battery top up, but thinking about it, it should be ideal if its collected from acid rain

 

 

You can also the melt water from a freezer or fridge. Unfortunately modern fridges & freezers don't ice up as much as the old ones used to.

[rusty69]

4 minutes ago, Flyboy said:

You can also the melt water from a freezer or fridge. Unfortunately modern fridges & freezers don't ice up as much as the old ones used to.

I'm all for saving a few quid, but is rainwater/freezer water as free from impurities as the shop sold stuff?

[MtB]

On 24/11/2017 at 10:31, rusty69 said:

I'm all for saving a few quid, but is rainwater/freezer water as free from impurities as the shop sold stuff?

 

I've heard the answer to this is no, as although distilled by definition, it picks up all manner of dust pollution on the way down. 

I'm not convinced by thsi though.

[MtB]

On 23/11/2017 at 19:53, Stephen Jeavons said:

 

Anyway just to clear any misunderstanding, the piping to and from the Eber is 22mm. Ditto to the rear radiators and calorifier. I only wish to use micro bore on two front radiators not the entire system. I hope that makes sense.

 

 

THis is unlikely to work well. Microbore and smallbore systems are designed differently and you're mixing the two up. Microbore systems have the flow and return from the boiler going to a pair of manifolds, then a pair of pipes runs off from the manifold to each radiator. A LOT of thin pipes!

Your way, the long microbore run will have a LOT of hydraulic resistance, far more than the local 22 and 15 mm loop, so the local loop will need heavily restricting to force any water to go along the long microbore run. Better to do it the other way around. 22mm run to the distant rads, microbore to the local rad and calorifier. 

 

[RLWP]

21 hours ago, Tony Brooks said:

I would go further and say the greater the pressure a pump has to act agains the higher its current consumption

If it's a centrifugal pump, the opposite is true. If it cannot deliver water, it uses less current

A young, apprentice Richard used to test experimental centrifugal pumps for aero engines. He was trained to always make sure the fuel output was shut before starting the rig. otherwise it would either wreck the motor or shear the drive shaft to the pump. 39,000 RPM takes a lot of power

Richard

[nicknorman]

5 minutes ago, RLWP said:

If it's a centrifugal pump, the opposite is true. If it cannot deliver water, it uses less current

A young, apprentice Richard used to test experimental centrifugal pumps for aero engines. He was trained to always make sure the fuel output was shut before starting the rig. otherwise it would either wreck the motor or shear the drive shaft to the pump. 39,000 RPM takes a lot of power

Richard

Interesting, I hadn’t thought of that before, but it makes sense. If there’s no output flow, the pump is just spinning water around and there are only frictional losses. Once there is flow, new water arrives all the time and has to be spun, taking quite a bit of power to do so due to its mass / angular momentum.

[nb Innisfree]

 

If the output of a centrifugal pump is shut off on a fire appliance the water in the pump casing can rapidly boil, usually a bypass prevents this. All the energy put into a centrifugal pump has to be absorbed, used either in water delivery or heat production. 

[MtB]

On 24/11/2017 at 10:42, RLWP said:

If it's a centrifugal pump, the opposite is true. If it cannot deliver water, it uses less current

A young, apprentice Richard used to test experimental centrifugal pumps for aero engines. He was trained to always make sure the fuel output was shut before starting the rig. otherwise it would either wreck the motor or shear the drive shaft to the pump. 39,000 RPM takes a lot of power

Richard

 

Seconded. 

In my line of business a heating pump is centrifugal, and has three speed settings. Changing the pump speed makes the tone of the pump change normally. When there is no circulation (for whatever reason), changing the pump speed makes no difference to the tone as it is doing no work. It runs at full speed whatever the 'speed' setting. I concluded this makes sense decades ago for the same reason Richard says.

The opposite occurs with positive displacement pumps, obviously.

[nb Innisfree]

I would imagine a ch pump doesn't really pump, rather it circulates, designed with plenty of 'slip' to prevent overload. 

[Tony Brooks]

4 hours ago, RLWP said:

If it's a centrifugal pump, the opposite is true. If it cannot deliver water, it uses less current

A young, apprentice Richard used to test experimental centrifugal pumps for aero engines. He was trained to always make sure the fuel output was shut before starting the rig. otherwise it would either wreck the motor or shear the drive shaft to the pump. 39,000 RPM takes a lot of power

Richard

and others.

I agree that when it finally does what I call cavitate because the rotor is just spinning in a sealed column of water but what happens when it is still moving water but against more pressure because of say a pipe restriction.

Genuine question because I have never tested such things but I would have thought it would load the motor to some degree and that implies more current.

[RLWP]

1 hour ago, Tony Brooks said:

and others.

I agree that when it finally does what I call cavitate because the rotor is just spinning in a sealed column of water but what happens when it is still moving water but against more pressure because of say a pipe restriction.

Genuine question because I have never tested such things but I would have thought it would load the motor to some degree and that implies more current.

It does as I described. We tested pumps by throttling the output to reduce the load

Richard 

[Tony Brooks]

Thanks Richard.

[Ex Brummie]

If the OP is only using 10mm for the last few feet, then 10mm may be a help. Working on a friends Mikuni 40, which is piped in 22mm, the volume of water takes forever to rise to an acceptable level of comfort. As long as there is enough large pipework to give satisfactory protection to the appliance, you don't need to flood the system.

[MtB]

10 minutes ago, Ex Brummie said:

If the OP is only using 10mm for the last few feet, then 10mm may be a help. Working on a friends Mikuni 40, which is piped in 22mm, the volume of water takes forever to rise to an acceptable level of comfort. As long as there is enough large pipework to give satisfactory protection to the appliance, you don't need to flood the system.

 

What on earth does this mean!!!

[nicknorman]

17 minutes ago, Ex Brummie said:

If the OP is only using 10mm for the last few feet, then 10mm may be a help. Working on a friends Mikuni 40, which is piped in 22mm, the volume of water takes forever to rise to an acceptable level of comfort. As long as there is enough large pipework to give satisfactory protection to the appliance, you don't need to flood the system.

The problem is that in order to encourage the flow to go down the 10mm pipes to the rads at the end of the run, you will have to throttle the rads near the boiler by turning down their lock shield valves (ie balancing the system) and so the point of the larger bore pipes to the rads nearer the boiler is somewhat lost. It would have been better if the near rads were in 10mm and the distant ones in 15mm but hey ho, it is what it is!

[Ex Brummie]

It means that if you have, for instance, large bore pipework to the calorifier, then using large bore over the rest of the system, increases the volume of water that the relatively small heat source has to heat, thus taking longer to reach a comfort temperature. The webasto recommendation is presumably to protect the boiler from overheating. Once this objective is achieved, the less volume you have aids efficiency. This is the thinking behind microbore and manifolds in a domestic house.

[MtB]

5 minutes ago, nicknorman said:

The problem is that in order to encourage the flow to go down the 10mm pipes to the rads at the end of the run, you will have to throttle the rads near the boiler by turning down their lock shield valves (ie balancing the system) and so the point of the larger bore pipes to the rads nearer the boiler is somewhat lost. It would have been better if the near rads were in 10mm and the distant ones in 15mm but hey ho, it is what it is!

 

As explained in post 37