Thursday, 22 December 2011

Suction pipe size

Never decrease the size of the suction of any pump, especially a centrifugal pump.

One of the most common mistakes we find when inspecting a pump which has failed prematurely is that the customer has decreased the suction size of the pump.

A pump with a 1" suction size should never be reduced to anything smaller than 1".

We always increase the suction pipe size in installations we do. A 1" pump suction would be fitted with a 1 1/4"or even a 1 1/2" pipe size. This ensures that the pump receives adequate fluid and that it operates at full design efficiency. A smaller suction pipe than the designed pump inlet will create cavitation, this in turn will create a vibration on the seal and the bearings.

Premature failure will result every time.

The next common problem on suction piping is the length of the suction pipe.

Always try to place the pump as close to the tank from which it is drawing the fluid. Try not to have any bends and limit the valves to one isolation and one non return if necessary. Also be very sure never to install a valve with a reduced bore. Ball valves can be purchesed with reduced or full bore. Make sure the suction valve is always a full bore.

Stick to these rules and you will have a happy pump unit.

For more assistance call 0826519841 or check out http://www.pedrollopumps.com/

2 comments:

  1. In June 2008 we decided to purchase a water pump submersible to be installed in our well of drinkable water. We did a market survey and found out that although the price, this brand pumps offered some assurance of quality. In some cases the price difference came to be 1/3 of the price that the pump Pedrollo Sumo cost. The Water Pump Pedrollo cost 1,084€, while other brands had pumps with the same details for 350€. We decided to invest in quality in order to have a pump that lasts several years.
    In April 2013, the pump motor burned, because of a water leak into the pump frame!! So the Pump Pedrollo Sumo didn’t even lasted five years. Lasted precisely four years and 10 months.
    So a Pump who cost the triple of the price of another cheaper brand at least should last double if not triple of the time. Considering that a cheap pump would last twice as long as the warranty, so….four years and considering that Pedrollo pump should last at least triple the time of cheap pump, then the Pedrollo pump should at least 12 YEARS ....

    Come into contact with Pedrollo directly to Italy and we were told that was already passed the warranty period and lamentably all the situation but couldn’t do nothing. We were also told that at some point Pedrollo identified several problems with these pumps, but nothing was said to the customer, like an honest brand would do!!!!! Right?????
    What is at stake is not warranty and obligatoriness to provide assistance, but is the "good" name of the brand and the quality of their products. So it becomes obvious that the Water Pumps Pedrollo not have the quality that should have according the price they cost, which in itself is quite high.
    So in short what I’m trying to show with our experience is if you buy a pump Pedrollo you take the risk that only last 5 years and no more. But off course if you buy a chipper pump, lets say 1/3 of the price for shore it going to last at least four years and perhaps more……

    ReplyDelete
  2. We responded to this complaint directly but the writer has chosen to ignore our mail....

    Good day Joao,
    Thank you for your post.
    It is common for users to blame pump failures on the pump unit itself without providing the full information.
    This writer does not represent Pedrollo Pumps in your territory, however he has over 38 years of experience in this field and is able to assist you in
    determining the reason for failure. Please note that a pump does not normally leak water into a motor after successfully operating for 5 years.
    Normally there are other factors which lead to the failure.

    Should you really wish to understand your problem, please describe the pump installation.
    Please answer the following questions:-
    1) How deep is the pump submerged?
    2) What is the measurement from the top of the water level in the pump sump (Lowest/highest)to the highest point the pump is required to pump?
    3) What is the length of the discharge pipe?
    4) Is there a non return valve installed on the discharge pipe?
    5) Is there an isolation valve installed on the discharge pipe?
    6) What is the internal diameter of the discharge pipe?
    7) Do you have an ammeter on the pump control panel? If so what was the operating amp reading when operating?
    8) Is there electrical overload protection built into the control panel?
    9) Please advise the model number of the installed pump and the voltage of the motor.

    Thank you for your post, we look forward to your responses. We are only responding to assist you in determining the real reason for the pump failure.

    Regards
    Evan Lewis
    (Evan Lewis & Associates CC administrators of www.pedrollopumps.com)
    Evan Lewis & Associates CC is an Independent Pedrollo Pump Supplier for SOUTHERN AFRICAN MARKETS only and not a Pedrollo S.P.A. owned business)

    ReplyDelete